As filed with the Securities and Exchange Commission on June 30, 2010

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number 811-21597

PRIMECAP ODYSSEY FUNDS
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(Exact name of registrant as specified in charter)

225 SOUTH LAKE AVENUE, SUITE 400
PASADENA, CA 91101
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(Address of principal executive offices) (Zip code)

DAVID H. VAN SLOOTEN
225 SOUTH LAKE AVENUE, SUITE 400
PASADENA, CA 91101
--------------------------------------
(Name and address of agent for service)

(626) 304-9222
Registrant's telephone number, including area code

Date of fiscal year end: OCTOBER 31

Date of reporting period: APRIL 30, 2010

ITEM 1. REPORTS TO STOCKHOLDERS.

SEMIANNUAL REPORT
FOR THE SIX MONTHS ENDED APRIL 30, 2010

LOGO PRIMECAP(R)
---------------ODYSSEY FUNDS

PRIMECAP ODYSSEY STOCK FUND
PRIMECAP ODYSSEY GROWTH FUND
PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND

TABLE OF CONTENTS
PRIMECAP ODYSSEY FUNDS
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Letter to Shareholders ...................................................... 2

Performance Graphs .......................................................... 9

Expense Example ............................................................. 12

Sector Breakdown ............................................................ 14

Schedule of Investments ..................................................... 16

PRIMECAP Odyssey Stock Fund ......................................... 16

PRIMECAP Odyssey Growth Fund ........................................ 20

PRIMECAP Odyssey Aggressive Growth Fund ............................. 24

Statements of Assets and Liabilities ........................................ 27

Statements of Operations .................................................... 28

Statement of Changes in Net Assets .......................................... 29

PRIMECAP Odyssey Stock Fund ......................................... 29

PRIMECAP Odyssey Growth Fund ........................................ 30

PRIMECAP Odyssey Aggressive Growth Fund ............................. 31

Financial Highlights ........................................................ 32

PRIMECAP Odyssey Stock Fund ......................................... 32

PRIMECAP Odyssey Growth Fund ........................................ 33

PRIMECAP Odyssey Aggressive Growth Fund ............................. 34

Notes to Financial Statements ............................................... 35

Additional Information ...................................................... 43

Management .................................................................. 44

LETTER TO SHAREHOLDERS
PRIMECAP ODYSSEY FUNDS
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DEAR FELLOW SHAREHOLDERS,

For the six months ended April 30, 2010, each of the three PRIMECAP Odyssey
Funds outperformed the unmanaged Standard & Poor's 500 Composite Stock Price
Index (S&P 500). The PRIMECAP Odyssey Stock Fund, PRIMECAP Odyssey Growth Fund,
and PRIMECAP Odyssey Aggressive Growth Fund produced total returns of +17.18%,
+19.81%, and +28.63%, respectively. By comparison, the unmanaged S&P 500
produced a total return of +15.66% for the period.

During the six months ended April 30, 2010, the stock market continued its
recovery from the financial crisis that began in mid-2007. The S&P 500 was up
almost 80% from its low point in March 2009, but it was still down almost 20%
from its peak in October 2007. The two best performing sectors in the S&P 500
during the six months ended April 30, 2010 were the consumer discretionary and
industrial sectors, which benefited from the improvement in retail sales and the
rebuilding of inventory levels as the economy recovered from the recession that
began in late 2007.

The PRIMECAP Odyssey Funds are focused on investing in high quality companies
that, in our judgment, offer better growth prospects than are anticipated by the
market. We remain overweight in the health care sector and underweight in the
financials, consumer staples, and energy sectors in each of the three PRIMECAP
Odyssey Funds. We are also overweight in the information technology sector in
both the PRIMECAP Odyssey Growth Fund and PRIMECAP Odyssey Aggressive Growth
Fund.

During the first six months of this fiscal year, relative returns in the
PRIMECAP Odyssey Stock Fund benefited from favorable stock selection and an
overweight position in the industrials sector. Stock selection in the health
care and information technology sectors were the largest contributors to
relative returns in the PRIMECAP Odyssey Growth Fund and PRIMECAP Odyssey
Aggressive Growth Fund. Each of the PRIMECAP Odyssey Funds also benefited from
underweight positions in the consumer staples and energy sectors.

A more detailed discussion of the results of each PRIMECAP Odyssey Fund follows.

LETTER TO SHAREHOLDERS
PRIMECAP ODYSSEY FUNDS
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CONTINUED

PRIMECAP ODYSSEY STOCK FUND

From November 1, 2009 to April 30, 2010, the Stock Fund's total return of
+17.18% exceeded the S&P 500's total return of +15.66%. On a relative basis, our
overweight position and stock selection in the industrials sector and our
underweight position in the energy and consumer staples sectors benefited the
fund. This benefit was partially offset by our overweight position and poor
stock selection in the health care sector.

Five industrial companies were among the top 10 contributors to fund results,
including Boeing, Southwest Airlines, and Rockwell Automation. Boeing (+53.9%)
appears well-positioned to benefit from the expected growth in global air
travel, particularly in the emerging markets. The company is in the process of
introducing its new "787 Dreamliner" aircraft, which is more fuel-efficient than
current passenger planes. Earnings at Southwest Airlines (+57.0%) have rebounded
as air travel volumes recovered. Rockwell Automation (+50.1%), a provider of
industrial automation control and information solutions, has benefited from the
recovery in industrial production. Other top contributors included Whirlpool
(+53.8%), Dress Barn (+53.1%), and Medtronic (+23.5%).

On the negative side were Boston Scientific, Symantec, and GlaxoSmithKline.
Boston Scientific (-15.3%) earnings suffered from a 30-day recall of its
implantable cardiac defibrillators; the company had failed to receive approval
from the Food and Drug Administration for changes in its manufacturing process.
Symantec, a provider of security and storage software solutions, declined 4.6%.
GlaxoSmithKline, a pharmaceutical company, was down 6.9%.

LETTER TO SHAREHOLDERS
PRIMECAP ODYSSEY FUNDS
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CONTINUED

The top 10 holdings, which collectively represent 27.3% of the portfolio at the
period end, are listed below:

PRIMECAP ODYSSEY STOCK FUND ENDING % OF
TOP 10 HOLDINGS AS OF 4/30/10 TOTAL PORTFOLIO*
--------------------------------------------------------------
Eli Lilly & Co. 3.7

Roche Holding AG 3.6

Amgen Inc. 3.2

Marsh & McLennan Cos. 2.9

Medtronic Inc. 2.7

Whirlpool Corp. 2.5

Boeing Co. 2.4

Novartis AG (ADS) 2.3

Waters Corp. 2.1

Honeywell International Inc. 2.0
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TOTAL % OF PORTFOLIO 27.3%
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* The percentage is calculated by using the ending market value of the
security divided by the total investments of the fund. The total
percentage of portfolio may not sum due to rounding.

PRIMECAP ODYSSEY GROWTH FUND

From November 1, 2009 to April 30, 2010, the Growth Fund's total return was
+19.81% compared with the S&P 500's total return of +15.66% and the Russell 1000
Growth Index's total return of +15.79%. Positive stock selection in the health
care and information technology sectors was a major contributor to fund returns.
The fund also benefited from its underweight position in the consumer staples
and energy sectors. Favorable stock selection in the energy sector further
helped results.

Three of the top five contributors were in the health care sector: Dendreon
(+113.9%), Cepheid (+50.7%), and Immunogen (+24.2%). Dendreon received approval
from the Food and Drug Administration for Provenge, a new therapy for certain
men with advanced prostate cancer that uses their own immune systems to fight
the disease. Immunogen is a biotechnology company that is focused on developing
targeted anti-cancer therapies using its expertise in monoclonal antibodies.
Southwest Airlines (+57.0%) and LED lighting manufacturer Cree Inc. (+73.9%)
were the other top five contributors.

LETTER TO SHAREHOLDERS
PRIMECAP ODYSSEY FUNDS
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CONTINUED

Although our selections in the health care sector made a positive contribution
to returns for the six-month period, certain health care stocks were among the
largest detractors from the fund's results, including Boston Scientific
(-15.3%), SurModics (-27.4%), and Charles River Laboratories (-8.3%). FormFactor
(-11.7%) and Motorola (-17.5%) also hurt the fund's returns.

The top 10 holdings, which collectively represent 27.3% of the portfolio at the
period end, are listed below:

PRIMECAP ODYSSEY GROWTH FUND ENDING % OF
TOP 10 HOLDINGS AS OF 4/30/10 TOTAL PORTFOLIO*
--------------------------------------------------------------
Immunogen Inc. 4.0

Amgen Inc. 3.6

Roche Holding AG 3.3

Conceptus Inc. 2.7

Eli Lilly & Co. 2.7

Electronic Arts Inc. 2.5

Dendreon Corp. 2.3

Cepheid 2.2

Altera Corp. 2.1

Medtronic Inc. 1.9
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Total % of Portfolio 27.3%
--------------------------------------------------------------

* The percentage is calculated by using the ending market value of the
security divided by the total investments of the fund. The total
percentage of portfolio may not sum due to rounding.

PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND

From November 1, 2009 to April 30, 2010, the Aggressive Growth Fund's total
return was +28.63%. This compares favorably to the S&P 500's total return of
+15.66% and the Russell Midcap Growth Index's total return of +23.23%. Much of
the outperformance in the Aggressive Growth Fund came from the fund's positions
in the health care sector. Biotechnology companies Dendreon (+113.9%) and
Pharmacyclics (+289.2%) along with medical diagnostic tool companies Cepheid
(+50.7%) and OraSure Technologies (+94.5%) were among the top five contributors
to returns. The other top five contributor was American Italian Pasta (+44.8%),
which was the fund's largest position at the beginning of the period. The
company, which is the largest producer of private label dried pasta in the
country, has continued to experience strong profit growth.

LETTER TO SHAREHOLDERS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
CONTINUED

The fund's overweight position in the information technology sector and
underweight position in the financials sector also helped results. Favorable
stock selection in the consumer discretionary, information technology, and
financials sectors also contributed positively to fund returns.

On the negative side, an underweight position in consumer discretionary stocks
hurt the fund's results. Boston Scientific (-15.3%), SurModics (-27.4%), and
Monsanto (-5.5%) were among the biggest detractors from the fund's returns.
Monsanto, the leading producer of agricultural seeds and herbicides, has seen
earnings growth slow due to lower prices for its Roundup herbicide as well as
slower adoption of its next-generation seed technologies.

The top 10 holdings, which collectively represent 32.1% of the portfolio at the
period end, are listed below:

PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND ENDING % OF
TOP 10 HOLDINGS AS OF 4/30/10 TOTAL PORTFOLIO*
--------------------------------------------------------------
Dendreon Corp. 4.6

Immunogen 4.5

American Italian Pasta Co. (Cl A) 4.5

Cepheid 3.7

Roche Holding AG 3.6

Conceptus Inc. 3.1

Electronic Arts Inc. 2.6

Altera Corp. 1.9

BioMarin Pharmaceutical Inc. 1.9

Dyax Corp. 1.8
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Total % of Portfolio 32.1%
--------------------------------------------------------------

* The percentage is calculated by using the ending market value of the
security divided by the total investments of the fund. The total
percentage of portfolio may not sum due to rounding.

LETTER TO SHAREHOLDERS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
CONTINUED

OUTLOOK

We are mixed in our outlook after the strong recovery in the stock market over
the past year. While economic activity has improved and the financial markets
have stabilized significantly from a year ago, we are concerned that current
valuations in the stock market may be anticipating a stronger recovery than is
likely to occur.

Much of the improvement in economic activity has been due to a rebuilding of
inventory levels and a rebound in consumer spending from its nadir in the midst
of the worst financial crisis since the Great Depression. The recovery has been
further aided by various government programs to stimulate the purchase of homes
and automobiles. We fear that some of these actions are only pulling forward
future demand into the current period. Given the current high rate of
unemployment, flat home prices after major declines, anemic income growth, and
the likelihood of higher tax rates, it is uncertain that the current rate of
growth in the economy is sustainable.

Similarly, the stabilization of the financial markets resulted from dramatic and
unprecedented actions taken by the government along with the Federal Reserve's
near-zero interest rate policy. It is not clear to us that the rate of
improvement in the financial markets will be sustained once the numerous
government programs end and the Federal Reserve raises short-term interest
rates.

We are also concerned about the fiscal and monetary policies of governments both
abroad and in the United States. The recent problems in Greece and other
countries in Europe demonstrate the challenges of funding increases in
government spending that exceeds the growth rate of the broader economy. At
home, many state and municipal governments continue to face fiscal crises due to
their inability to fund their budgets. The federal government continues to
embark on broad programs that intervene with not only the financial markets but
also the broader economy at large. The extensive spending required to pay for
these programs may lead to a rise in inflation and a weaker U.S. dollar in the
future.

Despite these concerns about the economic environment, we believe there are
attractive investment opportunities in the equities market. Corporate earnings
have rebounded strongly from 2008-2009 levels, and many companies appear poised
to continue to grow earnings rapidly after paring expenses and strengthening
their balance sheets over the past few years. Also, despite the current issues
in Europe, we are also positive about the long-term impact of globalization and
the continued development of emerging markets, which we believe will increase
the size of global markets for goods and services. Finally, we remain
enthusiastic about the potential for innovation. We believe

LETTER TO SHAREHOLDERS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
CONTINUED

that companies that develop new technologies or intellectual capital that
increase productivity and improve the longevity and quality of life can grow
sales and profits more rapidly than anticipated by the market. In particular, we
remain positive about our extensive investments in the health care and
information technology sectors. These two sectors also represent areas where the
United States has a strong competitive advantage relative to the rest of the
world. We will continue to work diligently to identify the companies that we
believe will benefit more than expected from innovation, globalization, and
restructuring.

Sincerely,

PRIMECAP Management Company

- --------------------------------------------------------------------------------

THE FUNDS INVEST IN SMALLER COMPANIES, WHICH INVOLVE ADDITIONAL RISKS SUCH AS
LIMITED LIQUIDITY AND GREATER VOLATILITY. ALL FUNDS MAY INVEST IN FOREIGN
SECURITIES, WHICH INVOLVE GREATER VOLATILITY AND POLITICAL, ECONOMIC AND
CURRENCY RISKS, AND DIFFERENCES IN ACCOUNTING METHODS. MUTUAL FUND INVESTING
INVOLVES RISK, AND LOSS OF PRINCIPAL IS POSSIBLE. GROWTH STOCKS TYPICALLY ARE
MORE VOLATILE THAN VALUE STOCKS; HOWEVER, VALUE STOCKS HAVE A LOWER EXPECTED
GROWTH RATE IN EARNINGS AND SALES. PAST PERFORMANCE IS NOT A GUARANTEE OF FUTURE
RESULTS.

Please refer to the Schedule of Investments for details of fund holdings. Fund
holdings and sector allocations are subject to change at any time and are not
recommendations to buy or sell any security. Current and future portfolio
holdings are subject to risk.

The STANDARD & POOR'S 500 COMPOSITE STOCK PRICE INDEX is a broad based index of
500 stocks, which is widely recognized as representative of the market in
general. The RUSSELL 1000 GROWTH INDEX is an index that measures the performance
of those Russell 1000 companies with higher price-to-book ratios and higher
forecasted growth values. The RUSSELL MIDCAP GROWTH INDEX measures the
performance of those Russell Midcap companies with higher price-to-book ratios
and higher forecasted growth values. These indices do not incur expenses and are
not available for investment.

THE INFORMATION PROVIDED HEREIN REPRESENTS THE OPINIONS OF PRIMECAP MANAGEMENT
COMPANY AND IS NOT INTENDED TO BE A FORECAST OF FUTURE EVENTS, A GUARANTEE OF
FUTURE RESULTS, NOR INVESTMENT ADVICE.

(5/10)

PERFORMANCE GRAPH
PRIMECAP ODYSSEY STOCK FUND
----------------------------------------------------------------

The following chart compares the value of a hypothetical $10,000 investment in
the PRIMECAP Odyssey Stock Fund from November 1, 2004 (inception) to April 30,
2010, compared to the S&P 500 Index. This chart illustrates the performance of a
hypothetical $10,000 investment made on the fund's inception date and is not
intended to imply any future performance. The returns shown do not reflect the
deduction of taxes that a shareholder would pay on fund distributions or the
redemption of fund shares. The chart assumes reinvestment of capital gains and
dividends.

CHART OMITTED

PRIMECAP ODYSSEY S&P 500
STOCK FUND INDEX
- --------------------------------------------------------------------------------
11/1/04 $10,000 $10,000
1/31/05 10,610 10,493
4/30/05 10,490 10,324
7/31/05 11,530 11,064
10/31/05 11,480 10,868
1/31/06 12,767 11,581
4/30/06 13,047 11,914
7/31/06 12,496 11,658
10/31/06 13,487 12,643
1/31/07 14,158 13,261
4/30/07 14,632 13,729
7/31/07 14,673 13,539
10/31/07 15,359 14,483
1/31/08 13,769 12,955
4/30/08 13,799 13,088
7/31/08 13,544 12,038
10/31/08 10,332 9,256
1/31/09 9,116 7,950
4/30/09 10,095 8,465
7/31/09 11,496 9,633
10/31/09 12,042 10,161
1/31/10 12,793 10,583
4/30/10 14,110 11,752

TOTAL RETURN
PERIOD ENDED APRIL 30, 2010
--------------------------------
ANNUALIZED
SINCE INCEPTION
1 YEAR 5 YEAR (11/01/04)
------- ------- --------------
PRIMECAP Odyssey Stock Fund 39.78% 6.11% 6.47%

S&P 500 Index* 38.84% 2.63% 2.99%

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE
FUTURE RESULTS. THE INVESTMENT RETURN AND PRINCIPAL VALUE OF AN INVESTMENT WILL
FLUCTUATE SO THAT AN INVESTOR'S SHARES, WHEN REDEEMED, MAY BE WORTH MORE OR LESS
THAN THEIR ORIGINAL COST. CURRENT PERFORMANCE OF THE FUND MAY BE LOWER OR HIGHER
THAN THE PERFORMANCE QUOTED. PERFORMANCE DATA CURRENT TO THE MOST RECENT MONTH
END MAY BE OBTAINED BY CALLING 1-800-729-2307. THE FUNDS IMPOSE A 2% REDEMPTION
FEE ON SHARES HELD LESS THAN 60 DAYS. PERFORMANCE FIGURES REFLECT THE FEE WAIVER
IN EFFECT AND, IN THE ABSENCE OF FEE WAIVERS, TOTAL RETURNS WOULD BE LOWER.
SHORT-TERM PERFORMANCE, IN PARTICULAR, IS NOT A GOOD INDICATION OF A FUND'S
FUTURE PERFORMANCE, AND AN INVESTMENT SHOULD NOT BE MADE BASED SOLELY ON PAST
RETURNS.

- -------------
* The S&P 500 Index is an unmanaged index composed of 500 common stocks
weighted by market value; its total return includes reinvestment of
dividends and is considered representative of the stock market return as
a whole.

PERFORMANCE GRAPH
PRIMECAP ODYSSEY GROWTH FUND

The following chart compares the value of a hypothetical $10,000 investment in
the PRIMECAP Odyssey Growth Fund from November 1, 2004 (inception) to April 30,
2010, compared to the S&P 500 Index. This chart illustrates the performance of a
hypothetical $10,000 investment made on the fund's inception date and is not
intended to imply any future performance. The returns shown do not reflect the
deduction of taxes that a shareholder would pay on fund distributions or the
redemption of fund shares. The chart assumes reinvestment of capital gains and
dividends.

CHART OMITTED

PRIMECAP ODYSSEY S&P 500
GROWTH FUND INDEX
- --------------------------------------------------------------------------------
11/1/04 $10,000 $10,000
1/31/05 10,550 10,493
4/30/05 10,450 10,324
7/31/05 11,540 11,064
10/31/05 11,620 10,868
1/31/06 12,908 11,581
4/30/06 13,208 11,914
7/31/06 12,688 11,658
10/31/06 13,769 12,643
1/31/07 14,420 13,261
4/30/07 14,845 13,729
7/31/07 14,764 13,539
10/31/07 15,898 14,483
1/31/08 13,807 12,955
4/30/08 13,919 13,088
7/31/08 13,359 12,038
10/31/08 10,246 9,256
1/31/09 9,200 7,950
4/30/09 10,262 8,465
7/31/09 12,039 9,633
10/31/09 12,437 10,161
1/31/10 13,274 10,583
4/30/10 14,901 11,752

TOTAL RETURN
PERIOD ENDED APRIL 30, 2010
--------------------------------
ANNUALIZED
SINCE INCEPTION
1 YEAR 5 YEAR (11/01/04)
------- ------- --------------

PRIMECAP Odyssey Growth Fund 45.20% 7.35% 7.53%

S&P 500 Index* 38.84% 2.63% 2.99%

PERFORMANCE GRAPH
PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND

The following chart compares the value of a hypothetical $10,000 investment in
the PRIMECAP Odyssey Aggressive Growth Fund from November 1, 2004 (inception) to
April 30, 2010, compared to the S&P 500 Index. This chart illustrates the
performance of a hypothetical $10,000 investment made on the fund's inception
date and is not intended to imply any future performance. The returns shown do
not reflect the deduction of taxes that a shareholder would pay on fund
distributions or the redemption of fund shares. The chart assumes reinvestment
of capital gains and dividends.

CHART OMITTED

PRIMECAP ODYSSEY S&P 500
AGGRESSIVE GROWTH FUND INDEX
- --------------------------------------------------------------------------------
11/1/04 $10,000 $10,000
1/31/05 10,500 10,493
4/30/05 9,890 10,324
7/31/05 11,220 11,064
10/31/05 11,240 10,868
1/31/06 12,790 11,581
4/30/06 13,110 11,914
7/31/06 12,310 11,658
10/31/06 13,920 12,643
1/31/07 14,915 13,261
4/30/07 15,280 13,729
7/31/07 14,915 13,539
10/31/07 16,253 14,483
1/31/08 13,205 12,955
4/30/08 13,134 13,088
7/31/08 12,685 12,038
10/31/08 9,654 9,256
11/30/08 8,623 8,591
12/31/08 9,491 8,682
1/31/09 9,174 7,950
4/30/09 10,113 8,465
7/31/09 12,276 9,633
10/31/09 12,583 10,161
1/31/10 13,838 10,583
4/30/10 16,185 11,752

S&P 500 Index* 38.84% 2.63% 2.99%

EXPENSE EXAMPLE
PRIMECAP ODYSSEY FUNDS
----------------------------------------------------------------
(UNAUDITED)

As a shareholder of one or more of the funds, you incur ongoing costs, including
management fees and other fund expenses. This expense example is intended to
help you understand your ongoing costs (in dollars) of investing in the funds
and to compare these costs with the ongoing costs of investing in other mutual
funds.

The expense example is based on an investment of $1,000 invested for a six month
period beginning October 31, 2009 and held through April 30, 2010.

ACTUAL EXPENSES

The information in the table adjacent to the heading "Actual Performance"
provides actual account values and actual expenses. You may use the information
in these columns, together with the amount you invested, to estimate the
expenses that you paid over the period. Simply divide your account value by
$1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then
multiply the result by the number in the column entitled "Expenses Paid during
Period" to estimate the expenses you paid on your account during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The information in the table adjacent to the heading "Hypothetical Performance
(5% return before expenses)" provides hypothetical account values and
hypothetical expenses based on the funds' actual expense ratios and an assumed
rate of return of 5% per year before expenses, which are not the funds' actual
returns. The hypothetical account values and expenses may not be used to
estimate the actual ending account balance or expenses you paid for the period.
You may use this information to compare the ongoing costs of investing in the
funds and other mutual funds. To do so, compare these 5% hypothetical examples
with the 5% hypothetical examples that appear in the shareholder reports of the
other mutual funds.

Please note that the expenses shown in the table are meant to highlight your
ongoing costs only. Therefore, the information adjacent to the heading
"Hypothetical Performance (5% return before expenses)" is useful in comparing
ongoing costs only and will not help you determine the relative total costs of
owning different mutual funds. In addition, if transactional costs were
included, your costs would have been higher.

EXPENSE EXAMPLE
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
(UNAUDITED) - CONTINUED
EXPENSES EXPENSE
PAID RATIO
DURING DURING
BEGINNING ENDING PERIOD* PERIOD*
ACCOUNT ACCOUNT (10/31/09 (10/31/09
VALUE VALUE TO TO
(10/31/09) (04/30/10) 04/30/10) 04/30/10)
- --------------------------------------------------------------------------------

PRIMECAP ODYSSEY STOCK FUND
Actual Performance $1,000.00 $1,171.80 $3.87 0.72%
Hypothetical Performance
(5% return before expenses) $1,000.00 $1,021.23 $3.60 0.72%

PRIMECAP ODYSSEY GROWTH FUND
Actual Performance $1,000.00 $1,198.10 $3.67 0.67%
Hypothetical Performance
(5% return before expenses) $1,000.00 $1,021.45 $3.38 0.67%

PRIMECAP ODYSSEY AGGRESSIVE
GROWTH FUND
Actual Performance $1,000.00 $1,286.30 $4.03 0.71%
Hypothetical Performance
(5% return before expenses) $1,000.00 $1,021.27 $3.56 0.71%
- --------------------------------------------------------------------------------

- -------------
* Expenses are equal to a fund's annualized expense ratio as indicated,
multiplied by the average account value over the period, multiplied by
the number of days in the most recent fiscal half-year period (181), then
divided by the number of days in the fiscal year (365) to reflect the
one-half year period.

SECTOR BREAKDOWN
PRIMECAP ODYSSEY FUNDS
----------------------------------------------------------------

PRIMECAP ODYSSEY STOCK FUND
----------------------------------------------------------------
Consumer Discretionary 13.1%

Consumer Staples 1.5%

Energy 5.5%

Financials 5.4%

Health Care 22.6%

Industrials 15.0%

Information Technology 18.4%

Materials 7.4%

Telecommunication Services 0.1%

Short Term Investments and Other Net Assets 11.0%
----------------------------------------------------------------
TOTAL 100.0%
----------------------------------------------------------------

PRIMECAP ODYSSEY GROWTH FUND
----------------------------------------------------------------
Consumer Discretionary 7.4%

Consumer Staples 0.1%

Energy 5.1%

Financials 2.9%

Health Care 37.0%

Industrials 8.5%

Information Technology 27.4%

Materials 2.5%

Telecommunication Services 0.1%

Short Term Investments and Other Net Assets 9.0%
----------------------------------------------------------------
TOTAL 100.0%
----------------------------------------------------------------

The tables above list sector allocations as a percentage of each fund's total
investments as of April 30, 2010. The management report makes reference to
average allocations during the period. As a result, the sector allocations above
may differ from those discussed in the management report.

SECTOR BREAKDOWN
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
CONTINUED

PRIMECAP Odyssey Aggressive Growth Fund
----------------------------------------------------------------
Consumer Discretionary 3.6%

Consumer Staples 4.7%

Energy 2.9%

Financials 1.5%

Health Care 40.2%

Industrials 8.4%

Information Technology 27.0%

Materials 1.7%

Telecommunication Services 0.2%

Short Term Investments and Other Net Assets 9.8%
----------------------------------------------------------------
Total 100.0%
----------------------------------------------------------------

The table above lists sector allocations as a percentage of the fund's total
investments as of April 30, 2010. The management report makes reference to
average allocations during the period. As a result, the sector allocations above
may differ from those discussed in the management report.

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY STOCK FUND
----------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED)

Shares Value
- --------------------------------------------------------------------------------
COMMON STOCKS - 89.0%

CONSUMER DISCRETIONARY - 13.1%
30,500 Amazon.com, Inc. (a) ................................... $ 4,180,330
70,700 Bed Bath & Beyond, Inc. (a) ............................ 3,249,372
171,900 CarMax, Inc. (a) ....................................... 4,223,583
145,400 Collective Brands, Inc. (a) ............................ 3,409,630
64,500 DIRECTV Group, Inc. (The) (a) .......................... 2,336,835
199,300 Dress Barn, Inc. (a) ................................... 5,516,624
32,200 Kohl's Corp. (a) ....................................... 1,770,678
72,200 Mattel, Inc............................................. 1,664,210
8,100 Men's Wearhouse, Inc.................................... 191,403
59,900 Sony Corp. - ADR ....................................... 2,049,778
61,000 TJX Cos, Inc............................................ 2,826,740
55,000 Walt Disney Co. (The) .................................. 2,026,200
71,400 Whirlpool Corp.......................................... 7,773,318
-----------
41,218,701
-----------
CONSUMER STAPLES - 1.5%
27,000 Kellogg Co.............................................. 1,483,380
25,000 PepsiCo, Inc............................................ 1,630,500
24,000 Procter & Gamble Co..................................... 1,491,840
-----------
4,605,720
-----------
ENERGY - 5.5%
40,000 Cenovus Energy, Inc..................................... 1,172,000
46,000 EnCana Corp............................................. 1,521,220
43,500 EOG Resources, Inc...................................... 4,877,220
44,000 National Oilwell Varco, Inc............................. 1,937,320
20,000 Noble Energy, Inc....................................... 1,528,000
60,000 Range Resources Corp.................................... 2,865,600
49,134 Schlumberger Ltd........................................ 3,509,150
-----------
17,410,510
-----------
FINANCIALS - 5.4%
45,000 Berkshire Hathaway, Inc. - Class B (a) ................. 3,465,000
54,000 Chubb Corp.............................................. 2,854,980
111,100 Discover Financial Services ............................ 1,717,606
371,750 Marsh & McLennan Cos, Inc............................... 9,003,785
-----------
17,041,371
-----------

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
16

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY STOCK FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED) -- CONTINUED

Shares Value
- --------------------------------------------------------------------------------
HEALTH CARE - 22.6%
75,000 Affymetrix, Inc. (a) ................................... $ 520,500
176,600 Amgen, Inc. (a) ........................................ 10,129,776
109,800 Biogen Idec, Inc. (a) .................................. 5,846,850
367,700 Boston Scientific Corp. (a) ............................ 2,529,776
330,100 Eli Lilly & Co.......................................... 11,543,597
84,000 GlaxoSmithKline PLC - ADR .............................. 3,132,360
46,000 Johnson & Johnson ...................................... 2,957,800
197,700 Medtronic, Inc.......................................... 8,637,513
140,950 Novartis AG - ADR ...................................... 7,167,308
17,000 Pfizer, Inc............................................. 284,240
71,616 Roche Holding AG - CHF ................................. 11,319,873
16,500 Sanofi Aventis - ADR ................................... 562,815
93,400 Waters Corp. (a) ....................................... 6,723,866
-----------
71,356,274
-----------
INDUSTRIALS - 15.0%
23,800 Alaska Air Group, Inc. (a) ............................. 985,558
50,000 Alexander & Baldwin, Inc................................ 1,779,000
253,000 AMR Corp. (a) .......................................... 1,867,140
45,000 Arkansas Best Corp...................................... 1,370,700
103,800 Boeing Co............................................... 7,518,234
23,500 Caterpillar, Inc........................................ 1,600,115
7,500 Deere & Co.............................................. 448,650
16,000 FedEx Corp.............................................. 1,440,160
133,300 Honeywell International, Inc............................ 6,327,751
23,500 JetBlue Airways Corp. (a) .............................. 131,365
140,000 McDermott International, Inc. (a) ...................... 3,837,400
6,200 Norfolk Southern Corp................................... 367,846
38,800 Pall Corp............................................... 1,512,812
55,300 Ritchie Bros. Auctioneers, Inc.......................... 1,294,020
74,000 Rockwell Automation, Inc................................ 4,493,280
427,400 Southwest Airlines Co................................... 5,633,132
1,900 Thomas & Betts Corp. (a) ............................... 79,686
24,000 Union Pacific Corp...................................... 1,815,840
68,400 United Parcel Service, Inc.............................. 4,729,176
----------
47,231,865
-----------

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
17

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY STOCK FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED) -- CONTINUED

Shares Value
- --------------------------------------------------------------------------------
INFORMATION TECHNOLOGY - 18.4%
20,550 Accenture Ltd. - Class A ............................... $ 896,802
180,000 Altera Corp............................................. 4,564,800
131,700 Applied Materials, Inc.................................. 1,814,826
40,321 ASML Holding N.V. - ADR ................................ 1,316,884
50,600 Corning, Inc............................................ 974,050
265,100 Electronic Arts, Inc. (a) .............................. 5,134,987
246,800 EMC Corp. (a) .......................................... 4,691,668
1,000 Google, Inc. (a) ....................................... 525,440
41,500 Hewlett-Packard Co...................................... 2,156,755
101,500 Intel Corp.............................................. 2,317,245
49,400 Intersil Corp........................................... 735,072
66,000 Intuit, Inc. (a) ....................................... 2,386,560
33,100 KLA-Tencor Corp......................................... 1,127,386
460,000 L.M. Ericsson Telephone Co. - ADR ...................... 5,290,000
156,100 Microsoft Corp.......................................... 4,767,294
112,900 Motorola, Inc........................................... 798,203
54,800 NeuStar, Inc. - Class A (a) ............................ 1,340,956
142,000 NVIDIA Corp. (a) ....................................... 2,232,240
88,500 Oracle Corp............................................. 2,286,840
22,200 Research In Motion Ltd. (a) ............................ 1,580,418
205,700 Symantec Corp. (a) ..................................... 3,449,589
235,500 Texas Instruments, Inc.................................. 6,125,355
47,400 Xilinx, Inc............................................. 1,221,972
24,800 Yahoo!, Inc. (a) ....................................... 409,944
-----------
58,145,286
-----------
MATERIALS - 7.4%
9,725 Domtar Corp. (a) ....................................... 688,919
24,300 Freeport-McMoRan Copper & Gold, Inc..................... 1,835,379
77,200 Monsanto Co............................................. 4,868,232
40,000 Newmont Mining Corp..................................... 2,243,200
21,400 Potash Corp. of Saskatchewan ........................... 2,364,700
20,000 Schweitzer-Mauduit International, Inc................... 1,138,400
109,993 Vulcan Materials Co..................................... 6,300,399
80,000 Weyerhauser Co.......................................... 3,961,600
-----------
23,400,829
-----------

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
18

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY STOCK FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED) -- CONTINUED

Shares Value
- --------------------------------------------------------------------------------
TELECOMMUNICATION SERVICES - 0.1%
115,750 Sprint Nextel Corp. (a) ............................. $ 491,938
-----------
TOTAL COMMON STOCKS
(Cost $244,471,558) ........................................... $ 280,902,494
-------------

Principal
Amount
- --------------------------------------------------------------------------------

SHORT TERM INVESTMENTS - 10.9%
$34,488,413 Dreyfus Treasury Prime Cash Management ........... $ 34,488,413
------------
TOTAL SHORT TERM INVESTMENTS
(Cost $34,488,413) ............................................ 34,488,413
------------
TOTAL INVESTMENTS
(Cost $278,959,971) - 99.9% ................................... 315,390,907
Other Assets in Excess of Liabilities - 0.1% .................... 244,838
-------------
TOTAL NET ASSETS: 100.0% ........................................ $ 315,635,745
=============

- ----------------
Percentages are stated as a percent of net assets.
ADR - American Depository Receipt.
CHF - Swiss Security.
(a) Non Income Producing.

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
19

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY GROWTH FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED)

Shares Value
- --------------------------------------------------------------------------------
COMMON STOCKS - 91.0%

CONSUMER DISCRETIONARY - 7.4%
250,000 99 Cents Only Stores (a) ............................ $ 3,880,000
77,900 Amazon.com, Inc. (a) ................................ 10,676,974
213,600 Bed Bath & Beyond, Inc. (a) ......................... 9,817,056
717,000 CarMax, Inc. (a) .................................... 17,616,690
60,000 Carnival Corp........................................ 2,502,000
166,200 DIRECTV Group, Inc. (The) (a) ....................... 6,021,426
357,900 Dress Barn, Inc. (a) ................................ 9,906,672
228,500 Gentex Corp.......................................... 4,910,465
55,850 Kohl's Corp. (a) .................................... 3,071,191
200,000 Mattel, Inc.......................................... 4,610,000
343,800 Quiksilver, Inc. (a) ................................ 1,832,454
252,100 Sony Corp. - ADR .................................... 8,626,862
63,000 TJX Cos, Inc......................................... 2,919,420
--------------
86,391,210
--------------
CONSUMER STAPLES - 0.1%
25,000 Procter & Gamble Co.................................. 1,554,000
--------------
Energy - 5.1%
70,000 Cenovus Energy, Inc.................................. 2,051,000
120,000 EnCana Corp.......................................... 3,968,400
115,400 EOG Resources, Inc................................... 12,938,648
60,000 Hess Corp............................................ 3,813,000
140,000 National Oilwell Varco, Inc.......................... 6,164,200
50,000 Noble Energy, Inc.................................... 3,820,000
170,000 Oceaneering International, Inc. (a) ................. 11,135,000
100,000 Range Resources Corp................................. 4,776,000
148,100 Schlumberger Ltd..................................... 10,577,302
--------------
59,243,550
--------------
FINANCIALS - 2.9%
29,000 Bank of New York Mellon Corp. (The) ................. 902,770
88,950 Berkshire Hathaway, Inc. - Class B (a) .............. 6,849,150
120,000 Chubb Corp........................................... 6,344,400
707,150 Marsh & McLennan Cos, Inc............................ 17,127,173
120,000 Progressive Corp. (The) ............................. 2,410,800
--------------
33,634,293
--------------

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
20

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY GROWTH FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED) -- CONTINUED

Shares Value
- --------------------------------------------------------------------------------
HEALTH CARE - 37.0%
810,000 Abiomed, Inc. (a) ................................... $ 7,808,400
1,610,000 Accuray, Inc. (a) ................................... 10,368,400
281,000 Affymetrix, Inc. (a) ................................ 1,950,140
727,200 Amgen, Inc. (a) ..................................... 41,712,192
232,300 Biogen Idec, Inc. (a) ............................... 12,369,975
298,200 BioMarin Pharmaceutical, Inc. (a) ................... 6,968,934
1,121,300 Boston Scientific Corp. (a) ......................... 7,714,544
1,320,100 Cepheid, Inc. (a) ................................... 26,388,799
140,000 Cerner Corp. (a) .................................... 11,887,400
43,248 Charles River Laboratories International, Inc. (a) .. 1,447,943
1,669,500 Conceptus, Inc. (a) ................................. 31,620,330
869,200 Crucell N.V. - ADR .................................. 18,261,892
505,000 Dendreon Corp. (a) .................................. 27,381,100
902,200 Eli Lilly & Co....................................... 31,549,934
88,800 GlaxoSmithKline PLC - ADR ........................... 3,311,352
220,000 Illumina, Inc. (a) .................................. 9,211,400
4,700,000 Immunogen, Inc. (a) ................................. 46,577,000
100,000 Johnson & Johnson ................................... 6,430,000
200,000 Kinetic Concepts, Inc. (a) .......................... 8,660,000
509,100 Medtronic, Inc....................................... 22,242,579
293,149 Micrus Endovascular Corp. (a) ....................... 5,886,432
1,190,000 Nektar Therapeutics (a) ............................. 6,612,400
260,800 Novartis AG - ADR ................................... 13,261,680
120,000 NuVasive, Inc. (a) .................................. 4,992,000
160,000 OraSure Technologies, Inc. (a) ...................... 1,014,400
247,632 Roche Holding AG - CHF .............................. 39,141,572
136,200 SurModics, Inc. (a) ................................. 2,533,320
146,500 Waters Corp. (a) .................................... 10,546,535
215,000 Wright Medical Group, Inc. (a) ...................... 4,037,700
--------------
431,888,353
--------------
INDUSTRIALS - 8.5%
1,617,300 AMR Corp. (a) ....................................... 11,935,674
280,000 C. H. Robinson Worldwide, Inc........................ 16,884,000
136,000 Caterpillar, Inc..................................... 9,260,240
187,565 Colfax Corp. (a) .................................... 2,447,723
180,000 Expeditors International Washington, Inc............. 7,333,200
50,600 FedEx Corp........................................... 4,554,506
284,550 JetBlue Airways Corp. (a) ........................... 1,590,635

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
21

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY GROWTH FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED) -- CONTINUED

Shares Value
- --------------------------------------------------------------------------------
INDUSTRIALS (CONTINUED)
260,000 McDermott International, Inc. (a) ................... $ 7,126,600
107,800 Pall Corp............................................ 4,203,122
221,700 Ritchie Bros. Auctioneers, Inc....................... 5,187,780
33,100 Rockwell Automation, Inc............................. 2,009,832
1,426,900 Southwest Airlines Co................................ 18,806,542
122,100 United Parcel Service, Inc........................... 8,441,994
--------------
99,781,848
--------------
INFORMATION TECHNOLOGY - 27.4%
57,850 Accenture Ltd. - Class A ............................ 2,524,574
84,000 Adobe Systems, Inc. (a) ............................. 2,821,560
200,000 Akamai Technologies, Inc. (a) ....................... 7,766,000
960,000 Altera Corp.......................................... 24,345,600
289,300 Applied Materials, Inc............................... 3,986,554
167,944 ASML Holding N.V. - ADR ............................. 5,485,051
138,000 Avid Technology, Inc. (a) ........................... 2,014,800
30,000 Cisco Systems, Inc. (a) ............................. 807,600
198,800 Corning, Inc......................................... 3,826,900
194,700 Cree, Inc. (a) ...................................... 14,253,987
37,000 Cymer, Inc. (a) ..................................... 1,263,550
1,488,500 Electronic Arts, Inc. (a) ........................... 28,832,245
783,700 EMC Corp. (a) ....................................... 14,898,137
1,360,000 Flextronics International Ltd. (a) .................. 10,540,000
629,700 FormFactor, Inc. (a) ................................ 9,451,797
39,410 Google, Inc. - Class A (a) .......................... 20,707,590
90,000 Hewlett-Packard Co................................... 4,677,300
185,500 Intel Corp........................................... 4,234,965
170,000 Intersil Corp. - Class A ............................ 2,529,600
390,400 Intuit, Inc. (a) .................................... 14,116,864
191,300 KLA-Tencor Corp...................................... 6,515,678
1,200,000 L.M. Ericsson Telephone Co. - ADR ................... 13,800,000
49,000 McAfee, Inc. (a) .................................... 1,702,750
42,000 Micron Technology, Inc. (a) ......................... 392,700
343,900 Microsoft Corp....................................... 10,502,706
208,200 Motorola, Inc. (a) .................................. 1,471,974
195,900 NeuStar, Inc. - Class A (a) ......................... 4,793,673
1,090,000 Nuance Communications, Inc. (a) ..................... 19,914,300
380,000 NVIDIA Corp. (a) .................................... 5,973,600
231,100 Oracle Corp.......................................... 5,971,624
70,000 QUALCOMM, Inc........................................ 2,711,800

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
22

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY GROWTH FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED) -- CONTINUED

Shares Value
- --------------------------------------------------------------------------------
INFORMATION TECHNOLOGY (CONTINUED)
409,800 Rambus, Inc. (a) .................................... $ 9,888,474
105,750 Research In Motion Ltd. (a) ......................... 7,528,343
151,800 SanDisk Corp. (a) ................................... 6,055,302
601,600 Stratasys, Inc. (a) ................................. 14,342,144
442,100 Symantec Corp. (a) .................................. 7,414,017
371,300 Texas Instruments, Inc............................... 9,657,513
200,000 Trimble Navigation Ltd. (a) ......................... 6,542,000
207,000 Xilinx, Inc.......................................... 5,336,460
--------------
319,599,732
--------------
MATERIALS - 2.5%
308,000 Monsanto Co.......................................... 19,422,480
17,250 Praxair, Inc......................................... 1,445,033
146,600 Vulcan Materials Co.................................. 8,397,248
--------------
29,264,761
--------------
TELECOMMUNICATION SERVICES - 0.1%
292,450 Sprint Nextel Corp. (a) ............................. 1,242,913
--------------
TOTAL COMMON STOCKS
(Cost $941,652,163) ........................................... $1,062,600,660
--------------

Principal
Amount
SHORT TERM INVESTMENTS - 9.5%
$110,376,292 Dreyfus Treasury Prime Cash Management ........ $ 110,376,292
--------------
TOTAL SHORT TERM INVESTMENTS
(Cost $110,376,292) ......................................... 110,376,292
--------------
TOTAL INVESTMENTS
(Cost $1,052,028,455) - 100.5% ................................ 1,172,976,952
Liabilities in Excess of Other Assets - (0.5)% .................. (5,716,994)
--------------
TOTAL NET ASSETS: 100.0% $1,167,259,958
==============

Percentages are stated as a percent of net assets.
ADR - American Depository Receipt.
CHF - Swiss Security.
(a) Non Income Producing.

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
23

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED) -- CONTINUED

Shares Value
- --------------------------------------------------------------------------------
COMMON STOCKS - 90.2%
CONSUMER DISCRETIONARY - 3.6%
63,000 Amazon.com, Inc. (a) ................................. $ 8,634,780
293,400 CarMax, Inc. (a) ..................................... 7,208,838
74,700 DIRECTV Group, Inc. (The) (a) ........................ 2,706,381
140,000 Gentex Corp........................................... 3,008,600
229,000 Quiksilver, Inc. (a) ................................. 1,220,570
-------------
22,779,169
-------------
CONSUMER STAPLES - 4.7%
736,866 American Italian Pasta Co. - Class A (a) ............. 28,907,253
152,405 Smart Balance, Inc. (a) .............................. 1,013,494
-------------
29,920,747
-------------
ENERGY - 2.9%
120,000 Cabot Oil & Gas Corp.................................. 4,335,600
32,000 EOG Resources, Inc.................................... 3,587,840
60,000 National Oilwell Varco, Inc........................... 2,641,800
74,000 Oceaneering International, Inc. (a) .................. 4,847,000
66,000 Range Resources Corp.................................. 3,152,160
-------------
18,564,400
-------------
FINANCIALS - 1.5%
605,820 MarketAxess Holdings, Inc............................. 9,523,490
-------------

HEALTH CARE - 40.2%
1,034,673 Abiomed, Inc. (a) .................................... 9,974,248
915,000 Accuray, Inc. (a) .................................... 5,892,600
222,000 Affymetrix, Inc. (a) ................................. 1,540,680
82,000 Biogen Idec, Inc. (a) ................................ 4,366,500
510,300 BioMarin Pharmaceutical, Inc. (a) .................... 11,925,711
1,069,800 Boston Scientific Corp. (a) .......................... 7,360,224
591,600 Cardica, Inc. (a) .................................... 1,419,840
1,172,800 Cepheid, Inc. (a) .................................... 23,444,272
1,053,850 Conceptus, Inc. (a) .................................. 19,959,919
536,407 Crucell N.V. (a) ..................................... 11,269,911
540,300 Dendreon Corp. (a) ................................... 29,295,066
3,225,000 Dyax Corp. (a) ....................................... 11,287,500
2,944,512 Immunogen, Inc. (a) .................................. 29,180,114
115,000 InterMune, Inc. (a) .................................. 4,894,400
198,500 Kinetic Concepts, Inc. (a) ........................... 8,595,050
476,300 Luminex Corp. (a) .................................... 7,744,638

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
24

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED) -- CONTINUED

Shares Value
- --------------------------------------------------------------------------------
HEALTH CARE (CONTINUED)
320,087 Micrus Endovascular Corp. (a) ........................ $ 6,427,347
641,800 Nektar Therapeutics (a) .............................. 8,959,528
115,000 NuVasive, Inc. (a) ................................... 4,784,000
1,642,600 OraSure Technologies, Inc. (a) ....................... 10,414,084
1,233,539 Pharmacyclics, Inc. (a) .............................. 9,362,561
147,700 Roche Holding AG - CHF ............................... 23,345,974
116,000 SurModics, Inc. (a) .................................. 2,157,600
220,000 Wright Medical Group, Inc. (a) ....................... 4,131,600
-------------
257,733,367
-------------
INDUSTRIALS - 8.4%
195,000 Alaska Air Group, Inc. (a) ........................... 8,074,950
1,207,500 AMR Corp. (a) ........................................ 8,911,350
116,000 C. H. Robinson Worldwide, Inc......................... 6,994,800
441,210 Colfax Corp. (a) ..................................... 5,757,790
745,425 JetBlue Airways Corp. (a) ............................ 4,166,926
53,000 Monster Worldwide, Inc. (a) .......................... 923,790
82,600 Pall Corp............................................. 3,220,574
155,400 Ritchie Bros. Auctioneers, Inc........................ 3,636,360
320,600 Southwest Airlines Co................................. 4,225,508
234,000 US Airways Group, Inc. (a) ........................... 1,654,380
400,000 Vitran Corp, Inc. (a) ................................ 6,076,000
-------------
53,642,428
-------------
INFORMATION TECHNOLOGY - 27.0%
140,000 3PAR, Inc. (a) ....................................... 1,306,200
180,000 Akamai Technologies, Inc. (a) ........................ 6,989,400
490,000 Altera Corp........................................... 12,426,400
214,588 ASML Holding N.V. - ADR .............................. 7,008,444
115,000 Avid Technology, Inc. (a) ............................ 1,679,000
145,600 Cree, Inc. (a) ....................................... 10,659,376
96,500 Cymer, Inc. (a) ...................................... 3,295,475
846,500 Electronic Arts, Inc. (a) ............................ 16,396,705
200,000 EMC Corp. (a) ........................................ 3,802,000
230,000 FARO Technologies, Inc. (a) .......................... 5,798,300
573,800 FormFactor, Inc. (a) ................................. 8,612,738
17,100 Google, Inc. (a) ..................................... 8,985,024
552,100 Guidance Software, Inc. (a) .......................... 3,246,348
113,800 Intermec, Inc. (a) ................................... 1,305,286
80,000 Internet Brands, Inc. (a) ............................ 828,000
255,000 Intuit, Inc. (a) ..................................... 9,220,800

THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
25

SCHEDULE OF INVESTMENTS
PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND
- --------------------------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED) -- CONTINUED

Shares Value
- --------------------------------------------------------------------------------
INFORMATION TECHNOLOGY (CONTINUED)
165,300 KLA-Tencor Corp....................................... $ 5,630,118
57,500 McAfee, Inc. (a) ..................................... 1,998,125
40,000 Micron Technology, Inc. (a) .......................... 374,000
149,200 NeuStar, Inc. - Class A (a) .......................... 3,650,924
440,000 Nuance Communications, Inc. (a) ...................... 8,038,800
286,550 NVIDIA Corp. (a) ..................................... 4,504,566
311,800 Rambus, Inc. (a) ..................................... 7,523,734
135,100 Research In Motion Ltd. (a) .......................... 9,617,769
111,700 SanDisk Corp. (a) .................................... 4,455,713
214,300 SonicWall, Inc. (a) .................................. 2,170,859
472,200 Stratasys, Inc. (a) .................................. 11,257,248
207,800 Symantec Corp. (a) ................................... 3,484,806
120,000 Trimble Navigation Ltd. (a) .......................... 3,925,200
200,000 Websense, Inc. (a) ................................... 4,554,000
25,000 Yahoo!, Inc. (a) ..................................... 413,250
-------------
173,158,608
-------------
MATERIALS - 1.7%
173,500 Monsanto Co........................................... 10,940,910
-------------
TELECOMMUNICATION SERVICES - 0.2%
296,700 Sprint Nextel Corp. (a) .............................. 1,260,975
-------------
TOTAL COMMON STOCKS
(Cost $476,190,986) .................................... $ 577,524,094
-------------

Principal
Amount
- --------------------------------------------------------------------------------

SHORT TERM INVESTMENTS - 10.1%
64,647,259 Dreyfus Treasury Prime Cash Management ............... $ 64,647,259
-------------
TOTAL SHORT TERM INVESTMENTS
(Cost $64,647,259) ..................................... 64,647,259
-------------
TOTAL INVESTMENTS
(Cost $540,838,245) - 100.3% ......................... 642,171,353
Liabilities in Excess of Other Assets - (0.3)% .................. (1,650,172)
-------------
TOTAL NET ASSETS: 100.0% ........................................ $ 640,521,181
=============
Percentages are stated as a percent of net assets.
ADR - American Depository Receipt.
CHF - Swiss Security.
(a) Non Income Producing.
THE ACCOMPANYING NOTES ARE AN INTEGRAL PART OF THESE FINANCIAL STATEMENTS.
26

STATEMENTS OF ASSETS AND LIABILITIES
PRIMECAP ODYSSEY FUNDS
----------------------------------------------------------------
APRIL 30, 2010 (UNAUDITED)

PRIMECAP PRIMECAP PRIMECAP
Odyssey Odyssey Odyssey Aggressive
Stock Fund Growth Fund Growth Fund
----- ---- ------ ---- ------ ----
ASSETS
Investments, at cost ................. $278,959,971 $1,052,028,455 $540,838,245
============ ============== ============

Investments, at value ................ $315,390,907 $1,172,976,952 $642,171,353
Receivables:
Securities sold .................... -- 3,930,719 --
Dividends and interest ............. 375,308 854,531 215,934
Fund shares sold ................... 1,181,758 7,682,432 3,714,031
Prepaid expenses and other assets .... 23,812 48,892 31,160
------------ -------------- ------------
Total assets ....................... 316,971,785 1,185,493,526 646,132,478
------------ -------------- ------------
LIABILITIES
Payable for securities purchased ... 438,069 11,003,284 4,514,850
Payable for fund shares repurchased 395,605 287,522 220,864
Payable to advisor (Note 6) ........ 403,945 1,373,848 751,282
Payable to the custodian ........... -- 5,354,125 --
Other accrued expenses & liabilities 98,421 214,789 124,301
------------ -------------- ------------
Total liabilities ................. 1,336,040 18,233,568 5,611,297
------------ -------------- ------------
NET ASSETS ........................... $315,635,745 $1,167,259,958 $640,521,181
============ ============== ============

Number of shares issued and
outstanding (unlimited shares
authorized, $0.01 par value) ....... 23,205,864 80,163,758 40,387,670
============ ============== ============

NET ASSET VALUE, OFFERING AND
REDEMPTION PRICE PER SHARE ......... $ 13.60 $ 14.56 $ 15.86
============ ============== ============

COMPONENTS OF NET ASSETS
Paid-in capital .................... $312,317,383 $1,058,378,971 $551,656,845
Undistributed net investment
income ............................ 851,489 1,199,721 --
Accumulated net realized loss
on investments .................... (33,968,680) (13,277,831) (12,475,879)
Accumulated net unrealized
appreciation on investments ....... 36,435,553 120,959,097 101,340,215
------------ -------------- ------------
Net assets ........................ $315,635,745 $1,167,259,958 $640,521,181
============ ============== ============

The accompanying notes are an integral part of these financial statements.
27

STATEMENTS OF OPERATIONS
PRIMECAP ODYSSEY FUNDS
----------------------------------------------------------------
FOR THE SIX MONTHS ENDED APRIL 30, 2010 (UNAUDITED)

PRIMECAP PRIMECAP PRIMECAP
Odyssey Odyssey Odyssey Aggressive
Stock Fund Growth Fund Growth Fund
INVESTMENT INCOME
Income
Dividends (net of foreign taxes
withheld of $119,891, $282,736,
and $95,254, respectively) ..... $ 2,250,876 $ 4,824,771 $ 917,657
Interest income .................. 5 13 8
----------- ------------ ------------
Total income .................... 2,250,881 4,824,784 917,665
----------- ------------ ------------
Expenses
Advisory fees ................... 754,868 2,516,931 1,346,496
Fund administration and
accounting costs ............... 64,694 229,320 117,690
Professional fees ............... 31,272 34,939 33,421
Shareholder servicing fees
and expenses ................... 44,597 143,760 106,613
Federal and state
registration fees .............. 16,147 16,509 14,373
Custody fees .................... 11,562 40,861 27,169
Trustee fees and expenses ....... 14,649 14,949 14,799
Printing and mailing ............ 7,293 21,025 23,272
Other expenses .................. 9,054 36,944 24,291
----------- ------------ ------------
Total expenses ................. 954,136 3,055,238 1,708,124
----------- ------------ ------------
NET INVESTMENT INCOME (LOSS) ... 1,296,745 1,769,546 (790,459)
----------- ------------ ------------
CHANGE IN REALIZED AND
UNREALIZED GAIN
ON INVESTMENTS
Net realized gain on investments 1,353,194 2,187,864 1,400,804
----------- ------------ ------------
Net unrealized appreciation
on investments ................. 35,986,474 153,072,991 115,674,216
----------- ------------ ------------
Net realized and unrealized gain
on investments ................. 37,339,668 155,260,855 117,075,020
----------- ------------ ------------
NET INCREASE IN NET ASSETS
RESULTING FROM OPERATIONS ...... $38,636,413 $157,030,401 $116,284,561
=========== ============ ============

The accompanying notes are an integral part of these financial statements.
28

STATEMENT OF CHANGES IN NET ASSETS
PRIMECAP ODYSSEY STOCK FUND
-----------------------------------------------------------------------------

SIX MONTHS
ENDED YEAR ENDED
APRIL 30, 2010(1) OCTOBER 31, 2009
-----------------------------------
INCREASE (DECREASE) IN NET ASSETS FROM:
OPERATIONS
Net investment income .................................. $ 1,296,745 $ 1,659,313
Net realized income (loss) on investments .............. 1,353,194 (28,008,473)
Net unrealized appreciation on investments ............. 35,986,474 47,825,757
------------ -------------
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS 38,636,413 21,476,597
------------ -------------
DISTRIBUTIONS TO SHAREHOLDERS
Net investment income .................................. (1,831,079) (1,193,169)
------------ -------------
TOTAL DISTRIBUTIONS TO SHAREHOLDERS ................... (1,831,079) (1,193,169)
------------ -------------
CAPITAL SHARE TRANSACTIONS
Proceeds from shares sold .............................. 111,118,033 100,416,214
Proceeds from reinvestment of distribution ............. 1,822,043 1,191,178
Cost of shares redeemed ................................ (13,783,915) (129,262,401)
Redemption fee proceeds ................................ 2,100 72,580
------------ -------------
NET INCREASE (DECREASE) FROM CAPITAL SHARE TRANSACTIONS 99,158,261 (27,582,429)
------------ -------------
TOTAL INCREASE (DECREASE) IN NET ASSETS ............... 135,963,595 (7,299,001)

NET ASSETS
Beginning of period .................................... 179,672,150 186,971,151
------------ -------------
End of period (includes undistributed net investment
income of $851,489 and $1,385,823, respectively) ...... $315,635,745 $ 179,672,150
============ =============

CHANGE IN CAPITAL SHARES
Shares outstanding, beginning of period ................ 15,370,380 18,503,767
------------ -------------
Shares sold ............................................ 8,762,395 10,460,306
Shares issued on reinvestment of distributions ......... 144,721 129,476
Shares repurchased ..................................... (1,071,632) (13,723,169)
------------ -------------
Net increase in capital shares ........................ 7,835,484 (3,133,387)
------------ -------------
Shares outstanding, end of period ...................... 23,205,864 15,370,380
============ =============

- -----------
(1) Unaudited.

The accompanying notes are an integral part of these financial statements.
29

STATEMENT OF CHANGES IN NET ASSETS
PRIMECAP ODYSSEY GROWTH FUND
---------------------------------------------------------------------------

SIX MONTHS
ENDED YEAR ENDED
APRIL 30, 2010(1) OCTOBER 31, 2009
------------------------------------
INCREASE (DECREASE) IN NET ASSETS FROM:
OPERATIONS
Net investment income ............................... $ 1,769,546 $ 1,697,113
Net realized income (loss) on investments ........... 2,187,864 (13,802,550)
Net unrealized appreciation on investments .......... 153,072,991 114,126,729
-------------- -------------
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS 157,030,401 102,021,292
-------------- -------------
DISTRIBUTIONS TO SHAREHOLDERS
Net investment income ............................... (1,825,837) (1,291,445)
-------------- -------------
TOTAL DISTRIBUTIONS TO SHAREHOLDERS ................ (1,825,837) (1,291,445)
-------------- -------------
CAPITAL SHARE TRANSACTIONS
Proceeds from shares sold ........................... 376,267,135 371,086,180
Proceeds from reinvestment of distribution .......... 1,740,542 1,224,200
Cost of shares redeemed ............................. (72,466,926) (178,976,597)
Redemption fee proceeds ............................. 24,866 46,291
-------------- -------------
NET INCREASE FROM CAPITAL SHARE TRANSACTIONS ....... 305,565,617 193,380,074
-------------- -------------
TOTAL INCREASE IN NET ASSETS ....................... 460,770,181 294,109,921

NET ASSETS
Beginning of period ................................. 706,489,777 412,379,856
-------------- -------------
End of year (including undistributed net investment
income of $1,199,721 and $1,256,012, respectively) $1,167,259,958 $ 706,489,777
============== =============

CHANGE IN CAPITAL SHARES
Shares outstanding, beginning of period ............. 57,986,448 40,960,083
-------------- -------------
Shares sold ........................................ 27,360,244 35,350,990
Shares issued on reinvestment of distributions ..... 132,765 132,203
Shares repurchased ................................. (5,315,699) (18,456,828)
-------------- -------------
Net increase in capital shares .................... 22,177,310 17,026,365
-------------- -------------
Shares outstanding, end of period ................... 80,163,758 57,986,448
============== =============

- ------------
(1) Unaudited.

The accompanying notes are an integral part of these financial statements.
30

STATEMENT OF CHANGES IN NET ASSETS
PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND
-------------------------------------------------------------------------

Six Months
Ended Year Ended
April 30, 2010(1) October 31, 2009
----------------------------------
INCREASE (DECREASE) IN NET ASSETS FROM:
OPERATIONS
Net investment loss ................................. $ (790,459) $ (1,419,736)
Net realized income (loss) on investments ........... 1,400,804 (10,430,012)
Net unrealized appreciation on investments .......... 115,674,216 85,726,892
------------ ------------
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS 116,284,561 73,877,144
------------ ------------
CAPITAL SHARE TRANSACTIONS
Proceeds from shares sold ........................... 194,182,629 125,071,901
Cost of shares repurchased .......................... (33,811,236) (60,586,982)
Redemption fee proceeds ............................. 34,435 40,419
------------ ------------
NET INCREASE FROM CAPITAL SHARE TRANSACTIONS ....... 160,405,828 64,525,338
------------ ------------
TOTAL INCREASE IN NET ASSETS ....................... 276,690,389 138,402,482

NET ASSETS
Beginning of period ................................. 363,830,792 225,428,310
------------ ------------
End of period ....................................... $640,521,181 $363,830,792
============ ============

CHANGE IN CAPITAL SHARES
Shares outstanding, beginning of period ............. 29,505,941 23,820,611
------------ ------------
Shares sold ........................................ 13,230,773 12,038,983
Shares repurchased ................................. (2,349,044) (6,353,653)
------------ ------------
Net increase in capital shares .................... 10,881,729 5,685,330
------------ ------------
Shares outstanding, end of period ................... 40,387,670 29,505,941
============ ============

- ------------
(1) Unaudited.

The accompanying notes are an integral part of these financial statements.
31

FINANCIAL HIGHLIGHTS
PRIMECAP ODYSSEY STOCK FUND
---------------------------------------------------------------------------------------------
FOR A CAPITAL SHARE OUTSTANDING THROUGHOUT THE PERIOD

THE FOLLOWING INFORMATION SHOULD BE READ IN CONJUNCTION WITH THE FINANCIAL STATEMENTS AND NOTES
THERETO APPEARING ELSEWHERE IN THIS SEMIANNUAL REPORT.

Net asset value, beginning of period ... $11.69 $10.10 $ 15.22 $13.48 $11.48 $ 10.00
------ ------ -------- ------ ------ -------
Income from investment operations:
Net investment income (loss) ......... 0.04 0.10 0.06 0.07 0.03 (0.01)
Net realized and unrealized
gain (loss) on investments .......... 1.96 1.55 (4.99) 1.79 1.97 1.49
------ ------ -------- ------ ------ -------
Total from investment operations ....... 2.00 1.65 (4.93) 1.86 2.00 1.48
------ ------ -------- ------ ------ -------
LESS DISTRIBUTIONS:
Dividends from net investment income . (0.09) (0.06) (0.07) (0.04) 0.00(4) 0.00
Distributions from realized gain ..... 0.00 0.00 (0.12) (0.08) 0.00(4) 0.00
------ ------ -------- ------ ------ -------

Total distributions .................... (0.09) (0.06) (0.19) (0.12) 0.00 0.00
------ ------ -------- ------ ------ -------
Redemption fee proceeds ................ 0.00(4) 0.00(4) 0.00(4) 0.00(4) 0.00(4) 0.00(4)
------ ------ -------- ------ ------ -------
Net asset value, end of period ......... $13.60 $11.69 $ 10.10 $15.22 $13.48 $ 11.48
====== ====== ======== ====== ====== =======

Total return ........................... 17.18%(3) 16.55% (32.73%) 13.88% 17.48% 14.80%

RATIOS/SUPPLEMENTAL DATA:
Net assets, end of period (millions) . $315.6 $179.7 $ 187.0 $216.4 $ 88.4 $ 30.1

RATIO OF EXPENSES TO AVERAGE NET ASSETS:
Before fees waived and expenses
absorbed or recouped ................ 0.72%(2) 0.80% 0.79% 0.81% 0.99% 1.80%
After fees waived and expenses
absorbed or recouped ................ 0.72%(2) 0.80% 0.79% 0.81% 0.99% 1.25%
RATIO OF NET INVESTMENT INCOME
(LOSS) TO AVERAGE NET ASSETS ......... 0.98%(2) 0.96% 0.51% 0.59% 0.41% (0.11%)

Portfolio turnover rate ................ 2.75%(3) 33.55% 9.66% 5.87% 4.09% 12.46%

- ------------
(1) Unaudited.
(2) Annualized.
(3) Not Annualized.
(4) Amount represents less than $0.01 per share.
(5) Commenced operations on November 1, 2004.

The accompanying notes are an integral part of these financial statements.
32

FINANCIAL HIGHLIGHTS
PRIMECAP ODYSSEY GROWTH FUND
----------------------------------------------------------------------------------------------
FOR A CAPITAL SHARE OUTSTANDING THROUGHOUT THE PERIOD

THE FOLLOWING INFORMATION SHOULD BE READ IN CONJUNCTION WITH THE FINANCIAL STATEMENTS AND NOTES
THERETO APPEARING ELSEWHERE IN THIS SEMIANNUAL REPORT.

Six Months Year Year Year Year Year
Ended Ended Ended Ended Ended Ended
Apr. 30, Oct. 31, Oct. 31, Oct. 31, Oct. 31, Oct. 31,
2010(1) 2009 2008 2007 2006 2005(5)
-------- ------ -------- ------ ------ -------
Net asset value, beginning of period ... $ 12.18 $10.07 $ 15.71 $13.76 $11.62 $ 10.00
-------- ------ -------- ------ ------ -------
INCOME FROM INVESTMENT OPERATIONS:
Net investment income (loss) ......... 0.02 0.03 0.03 0.04 0.01 (0.01)
Net realized and unrealized
gain (loss) on investments .......... 2.39 2.11 (5.59) 2.07 2.14 1.63
-------- ------ -------- ------ ------ -------
Total from investment operations ....... 2.41 2.14 (5.56) 2.11 2.15 1.62
-------- ------ -------- ------ ------ -------
LESS DISTRIBUTIONS:
Dividends from net investment income (0.03) (0.03) (0.04) (0.02) 0.00(4) 0.00
Distributions from realized gain ..... 0.00 0.00 (0.04) (0.14) (0.01) 0.00
-------- ------ -------- ------ ------ -------
Total distributions .................... (0.03) (0.03) (0.08) (0.16) (0.01) 0.00
-------- ------ -------- ------ ------ -------
Redemption fee proceeds ................ 0.00(4) 0.00(4) 0.00(4) 0.00(4) 0.00(4) 0.00(4)
-------- ------ -------- ------ ------ -------
Net asset value, end of period ......... $ 14.56 $12.18 $ 10.07 $15.71 $13.76 $ 11.62
======== ====== ======== ====== ====== =======

Total return ........................... 19.81%(3) 21.39% (35.55%) 15.46% 18.49% 16.20%

RATIOS/SUPPLEMENTAL DATA:
Net assets, end of period (millions) $1,167.3 $706.5 $ 412.4 $512.0 $202.2 $ 46.6

RATIO OF EXPENSES TO AVERAGE NET ASSETS:
Before fees waived and expenses
absorbed or recouped ................ 0.67%(2) 0.71% 0.71% 0.75% 0.89% 1.79%
After fees waived and expenses
absorbed or recouped ................ 0.67%(2) 0.71% 0.71% 0.75% 0.89% 1.25%
RATIO OF NET INVESTMENT INCOME
(LOSS) TO AVERAGE NET ASSETS ......... 0.39%(2) 0.35% 0.26% 0.30% 0.19% (0.27%)

Portfolio turnover rate ................ 2.31%(3) 12.49% 12.72% 4.83% 6.87% 8.84%

(1) Unaudited.
(2) Annualized.
(3) Not Annualized.
(4) Amount represents less than $0.01 per share.
(5) Commenced operations on November 1, 2004.

The accompanying notes are an integral part of these financial statements.
33

FINANCIAL HIGHLIGHTS
PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND
------------------------------------------------------------------------------------------------
FOR A CAPITAL SHARE OUTSTANDING THROUGHOUT THE PERIOD

THE FOLLOWING INFORMATION SHOULD BE READ IN CONJUNCTION WITH THE FINANCIAL STATEMENTS AND NOTES
THERETO APPEARING ELSEWHERE IN THIS SEMIANNUAL REPORT.

Six Months Year Year Year Year Year
Ended Ended Ended Ended Ended Ended
Apr. 30, Oct. 31, Oct. 31, Oct. 31, Oct. 31, Oct. 31,
2010(1) 2009 2008 2007 2006 2005(5)
---------- ------- -------- ------- ------- -------
Net asset value, beginning of period ... $ 12.33 $ 9.46 $ 16.03 $ 13.92 $ 11.24 $ 10.00
---------- ------- -------- ------- ------- -------
INCOME FROM INVESTMENT OPERATIONS:
Net investment loss .................. (0.02) (0.05) (0.06) (0.03) (0.02) (0.06)
Net realized and unrealized
gain (loss) on investments .......... 3.55 2.92 (6.42) 2.34 2.70 1.30
---------- ------- -------- ------- ------- -------
Total from investment operations ....... 3.53 2.87 (6.48) 2.31 2.68 1.24
---------- ------- -------- ------- ------- -------
LESS DISTRIBUTIONS:
Distributions from realized gain ..... 0.00 0.00 (0.09) (0.20) 0.00 0.00
---------- ------- -------- ------- ------- -------
Redemption fee proceeds ................ 0.00(4) 0.00(4) 0.00(4) 0.00(4) 0.00(4) 0.00(4)
---------- ------- -------- ------- ------- -------
Net asset value, end of period ......... $ 15.86 $ 12.33 $ 9.46 $ 16.03 $ 13.92 $ 11.24
========== ======= ======== ======= ======= =======

Total return ........................... 28.63%(3) 30.34% (40.60%) 16.76% 23.84% 12.40%

RATIOS/SUPPLEMENTAL DATA:
Net assets, end of period (millions) $ 640.5 $ 363.8 $ 225.4 $ 375.2 $ 119.9 $ 22.8

RATIO OF EXPENSES TO AVERAGE NET ASSETS:
Before fees waived and expenses
absorbed or recouped ................ 0.71%(2) 0.77% 0.78% 0.78% 0.99% 1.82%
After fees waived and expenses
absorbed or recouped ................ 0.71%(2) 0.77% 0.78% 0.78% 0.99% 1.25%
RATIO OF NET INVESTMENT LOSS
TO AVERAGE NET ASSETS ................ (0.33%)(2) (0.54%) (0.46%) (0.25%) (0.33%) (0.82%)

Portfolio turnover rate ................ 2.55%(3) 19.70% 24.32% 6.02% 12.30% 7.38%

(1) Unaudited.
(2) Annualized.
(3) Not Annualized.
(4) Amount represents less than $0.01 per share.
(5) Commenced operations on November 1, 2004.

The accompanying notes are an integral part of these financial statements.
34

NOTES TO FINANCIAL STATEMENTS
PRIMECAP ODYSSEY FUNDS
----------------------------------------------------------------
FOR THE SIX MONTHS ENDED APRIL 30, 2010 (UNAUDITED)

(1) ORGANIZATION

PRIMECAP Odyssey Funds (the "Trust") was organized on June 8, 2004 as a Delaware
statutory trust and is registered as an open-end management investment company
under the Investment Company Act of 1940, as amended (the "1940 Act"). The Trust
is comprised of three series: PRIMECAP Odyssey Stock Fund, PRIMECAP Odyssey
Growth Fund, and PRIMECAP Odyssey Aggressive Growth Fund (the "Funds"), each of
which is diversified within the meaning of the 1940 Act. PRIMECAP Management
Company (the "Investment Advisor") serves as investment advisor to the Funds.
The Funds commenced operations on November 1, 2004.

Each Fund's investment objective is to provide long-term capital appreciation.
Each Fund is authorized to issue unlimited shares of beneficial interest. All
shares within each Fund have equal rights with respect to voting.

(2) SIGNIFICANT ACCOUNTING POLICIES

The Funds consistently follow the accounting policies set forth below which are
in conformity with accounting principles generally accepted in the United States
of America.

A. SECURITY VALUATION

Securities traded on a national securities exchange are valued at the
last reported sales price at the close of regular trading on each day
the exchanges are open for trading. Securities listed on the NASDAQ
Global Market, the NASDAQ Global Select Market, and the NASDAQ Capital
Market are valued using the NASDAQ Official Closing Price, which may not
necessarily represent the last sale price. Quotations of foreign
securities in a foreign currency are valued daily in U.S. dollars on the
basis of the foreign currency exchange rates prevailing at the time such
valuation is determined. Foreign currency exchange rates generally are
determined prior to the close of the New York Stock Exchange (the
"NYSE"). Securities traded on an exchange for which there have been no
sales are valued at the mean between the bid and asked price. Securities
for which quotations are not readily available are stated at their
respective fair values as determined in good faith by a valuation
committee of the Investment Advisor in accordance with procedures
approved by the Trust's board of trustees. In determining fair value,
the Funds take into account all relevant factors and available
information. Consequently, the price of a security used by a Fund to
calculate its net asset value per share ("NAV") may differ from quoted
or published prices for the same security. Fair value pricing involves
subjective judgments, and there is no single standard for determining a
security's fair value. As a result, different mutual funds could
reasonably arrive at a different fair value for the same security. It is
possible that the fair value determined for a security is materially
different from the value that could be realized upon the sale of that
security or from the values that other mutual funds may determine.

Investments in other funds are valued at their respective net asset
values as determined by those funds, in accordance with the 1940 Act.

NOTES TO FINANCIAL STATEMENTS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------

FOR THE SIX MONTHS ENDED APRIL 30, 2010 (UNAUDITED) - CONTINUED

Foreign securities are recorded in the financial statements after
translation to U.S. dollars based on the applicable exchange rate at the
end of the period. The Funds do not isolate that portion of the results
of operations arising as a result of changes in the currency exchange
rate from the fluctuations arising as a result of changes in the market
prices of investments during the period.

B. SHARE VALUATION

The net asset value per share of a Fund is calculated by dividing the
sum of the value of the securities held by the Fund, plus cash or other
assets, minus all liabilities (including estimated accrued expenses) by
the total number of shares outstanding of the Fund. The result is
rounded to the nearest cent. The Funds' shares will not be priced on the
days on which the NYSE is closed for trading.

C. FOREIGN CURRENCY

Values of investments denominated in foreign currencies are converted
into U.S. dollars using the spot market rate of exchange at the time of
valuation. Purchases and sales of investments and dividend and interest
income are translated into U.S. dollars using the spot market rate of
exchange prevailing on the respective dates of such translations. The
gain or loss resulting from changes in foreign exchange rates is
included with net realized and unrealized gain or loss from investments,
as appropriate. Foreign securities and currency transactions may involve
certain considerations and risks not typically associated with those of
domestic origin.

D. FEDERAL INCOME TAXES

Each Fund has elected to be treated as a "regulated investment company"
under Subchapter M of the Internal Revenue Code. The Funds intend to
distribute substantially all of their taxable income and any capital
gains in excess of applicable capital loss carryforwards. Accordingly,
no provision for Federal income taxes has been made in the accompanying
financial statements.

The Funds may be subject to foreign taxes on income, gains on
investments, or currency repatriation, a portion of which may be
recoverable. The Funds will accrue such taxes and recoveries as
applicable based upon their current interpretations of the tax rules and
regulations that exist in the markets in which they invest.

There is no tax liability resulting from unrecognized tax benefits
relating to uncertain income tax positions taken or expected to be taken
on the tax return for the fiscal year-end October 31, 2009, or for any
other tax years which are open for exam. As of October 31, 2009, open
tax years include the tax years ended October 31, 2006 through 2009. The
Funds are also not aware of any tax positions for which it is reasonably
possible that the total amounts of unrecognized tax benefits will
significantly change in the next six months. The Funds recognize
interest and penalties, if any, related to unrecognized tax benefits as
income tax expense in the Statement of Operations. During the period,
the Funds did not incur any interest or penalties.

NOTES TO FINANCIAL STATEMENTS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------

FOR THE SIX MONTHS ENDED APRIL 30, 2010 (UNAUDITED) - CONTINUED

E. ALLOCATION OF EXPENSES

Each Fund is charged for those expenses directly attributable to it.
Expenses that are not directly attributable to a Fund are allocated
among the Funds in proportion to their respective assets or another
appropriate method.

F. SECURITY TRANSACTIONS, INVESTMENT INCOME, AND DISTRIBUTIONS

Security transactions are accounted for on the trade date. Dividend
income and distributions to shareholders are recorded on the ex-dividend
date, and interest income is recognized on the accrual basis. Realized
gains and losses are evaluated on the basis of identified costs.
Premiums and discounts on the purchase of securities are amortized/
accreted using the effective interest method. Accounting principles
generally accepted in the United States of America require that
permanent financial reporting and tax differences be reclassified in the
capital accounts.

G. USE OF ESTIMATES

The preparation of financial statements in conformity with accounting
principles generally accepted in the United States of America requires
management to make estimates and assumptions that affect the reported
amounts of assets and liabilities and disclosure of contingent assets
and liabilities at the date of the financial statements, and the
reported amounts of revenues and expenses during the reporting period.
Actual results could differ from these estimates.

H. INDEMNIFICATION OBLIGATIONS

Under the Trust's organizational documents, its current and former
officers and trustees are indemnified against certain liabilities
arising out of the performance of their duties to the Funds. In
addition, in the normal course of business, the Funds enter into
contracts that contain a variety of representations and warranties that
provide general indemnifications. The Funds' maximum exposure under
these arrangements is unknown as this would involve future claims that
may be made against the Funds that have not yet occurred. Based on
experience, the Funds would expect the risk of loss to be remote.

(3) INVESTMENT TRANSACTIONS

The cost of purchases and the proceeds from sales of securities, excluding
short-term investments, for the six months ended April 30, 2010 were as follows:

FUND PURCHASES SALES
- ---- --------- -----
PRIMECAP Odyssey Stock Fund ............... $ 80,396,334 $ 6,468,164
PRIMECAP Odyssey Growth Fund .............. $262,972,156 $19,314,883
PRIMECAP Odyssey Aggressive Growth Fund ... $132,955,229 $11,223,643

NOTES TO FINANCIAL STATEMENTS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
FOR THE SIX MONTHS ENDED APRIL 30, 2010 (UNAUDITED) - CONTINUED

(4) FAIR VALUE OF FINANCIAL INSTRUMENTS

The Funds follow a fair value hierarchy that distinguishes between market data
obtained from independent sources (observable inputs) and each Fund's own market
assumptions (unobservable inputs). These inputs are used in determining the
value of each Fund's investments and are summarized in the following fair value
hierarchy:

Level 1 - Quoted prices in active markets for identical securities.

Level 2 - Other significant observable inputs (including quoted prices
for similar securities, interest rates, prepayment speeds, credit
risk, etc.).

Level 3 - Significant unobservable inputs (including the Fund's own
assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of
the risk associated with investing in those securities.

The following is a summary of the inputs used as of April 30, 2010, in valuing
the Fund's investments carried at fair value:

Quoted prices Significant
in active other Significant
markets for observable unobservable
identical assets inputs inputs
Fund Description (Level 1) (Level 2) (Level 3) Total
- ---- ----------- --------- --------- --------- -----

PRIMECAP Common Stock $ 280,902,494 $ -- $ -- $ 280,902,494
Odyssey Stock Short-Term Investments $ 34,488,413 $ -- $ -- $ 34,488,413
(Fund) Total Investments
in Securities $ 315,390,907 $ -- $ -- $ 315,390,907

PRIMECAP Common Stock $1,062,600,660 $ -- $ -- $1,062,600,660
Odyssey Growth Short-Term Investments $ 110,376,292 $ -- $ -- $ 110,376,292
(Fund) Total Investments
in Securities $1,172,976,952 $ -- $ -- $1,172,976,952

PRIMECAP Common Stock $ 577,524,094 $ -- $ -- $ 577,524,094
Odyssey Short-Term Investments $ 64,647,259 $ -- $ -- $ 64,647,259
(Aggressive) Total Investments
(Growth Fund) in Securities $ 642,171,353 $ -- $ -- $ 642,171,353

- ---------
Refer to each Fund's respective Schedule of Investments for the breakdown of
major categories.

NOTES TO FINANCIAL STATEMENTS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------

FOR THE SIX MONTHS ENDED APRIL 30, 2010 (UNAUDITED) - CONTINUED

(5) DISTRIBUTION TO SHAREHOLDERS

Net investment income and net realized gains differ for financial statement and
tax purposes due to differing treatments of deferred wash sale losses.

As of October 31, 2009, the components of capital on a tax basis were as
follows:

PRIMECAP PRIMECAP PRIMECAP
Odyssey Odyssey Odyssey Aggressive
Stock Fund Growth Fund Growth Fund

Cost of investments
for tax purposes .............. $ 183,468,929 $ 742,113,539 $ 379,523,723
============= ============= =============
Gross tax unrealized
appreciation .................. 21,373,303 75,226,142 54,692,911
Gross tax unrealized
depreciation .................. (25,676,185) (111,380,245) (69,071,735)
------------- ------------- -------------
Net tax unrealized depreciation $ (4,302,882) $ (36,154,103) $ (14,378,824)
============= ============= =============

Currently distributable
ordinary income ............... $ 1,385,823 $ 1,256,012 $ --
Currently distributable long-term
capital gain .................. -- -- --
------------- ------------- -------------
Currently total distributable
earnings ...................... $ 1,385,823 $ 1,256,012 $ --
------------- ------------- -------------
Other accumulated loss .......... $ (30,569,914) $ (11,425,486) $ (13,831,859)
------------- ------------- -------------
Total accumulated loss .......... $ (33,486,973) $ (46,323,577) $ (28,210,683)
============= ============= =============

NOTES TO FINANCIAL STATEMENTS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
FOR THE SIX MONTHS ENDED APRIL 30, 2010 (UNAUDITED) - CONTINUED

U.S. Generally Accepted Accounting Principles (GAAP) require that certain
components of net assets relating to permanent differences be reclassified
between financial and tax reporting. These reclassifications have no effect on
net assets or net asset value per share. During the fiscal year ended October
31, 2009, the reclassifications were as follows:

UNDISTRIBUTED ACCUMULATED
NET INVESTMENT NET REALIZED
INCOME LOSS PAID IN CAPITAL
-------------- ------------ ---------------
PRIMECAP Odyssey
Stock Fund ............... 26,346 (2,388,622) 2,362,276
PRIMECAP Odyssey
Growth Fund .............. (23,664) 23,664 --
PRIMECAP Odyssey
Aggressive Growth Fund ... 1,419,736 (1,446) (1,418,290)

The permanent differences relate to net operating loss and foreign currency
adjustments and in-kind transfers of securities with differing book and tax
methods of accounting. During the year ended October 31, 2009, the PRIMECAP
Odyssey Stock Fund realized a $2,362,276 gain resulting from an in-kind transfer
of securities to the PRIMECAP Odyssey Growth Fund in connection with a
shareholder redemption. Because such gains are not taxable, the transaction
resulted in a permanent book-to-tax difference for the PRIMECAP Odyssey Stock
Fund.

At October 31, 2009, the PRIMECAP Odyssey Stock Fund, PRIMECAP Odyssey Growth
Fund, and PRIMECAP Odyssey Aggressive Growth Fund had capital loss carryovers of
$30,569,914, $11,425,486, and $13,831,859, respectively, of which $4,884,883,
$1,686,809, and $3,399,678 expire on October 31, 2016, and $25,685,031,
$9,738,677, and $10,432,181 expire on October 31, 2017, respectively.

Tax components of dividends paid during the six months ended April 30, 2010 and
the year ended October 31, 2009 were as follows:

APRIL 30, 2010
------------------------------
Ordinary Long-Term
Income Capital Gain
Distributions Distributions
------------- -------------
PRIMECAP Odyssey Stock Fund ................ $ 1,831,079 $ --
PRIMECAP Odyssey Growth Fund ............... $ 1,825,837 $ --
PRIMECAP Odyssey Aggressive Growth Fund .... $ -- $ --

OCTOBER 30, 2010
------------------------------
Ordinary Long-Term
Income Capital Gain
Distributions Distributions
------------- -------------
PRIMECAP Odyssey Stock Fund ................ $ 1,193,169 $ --
PRIMECAP Odyssey Growth Fund ............... $ 1,291,445 $ --
PRIMECAP Odyssey Aggressive Growth Fund .... $ -- $ --

NOTES TO FINANCIAL STATEMENTS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
FOR THE SIX MONTHS ENDED APRIL 30, 2010 (UNAUDITED) - CONTINUED

The Funds designated as long-term capital gain dividends, pursuant to Internal
Revenue Code Section 852(b)(3), the amounts necessary to reduce the earnings and
profits of the Funds related to net capital gains to zero for the tax year ended
October 31, 2009.

(6) INVESTMENT ADVISORY AND OTHER AGREEMENTS

The Trust has entered into an investment management agreement with the
Investment Advisor on behalf of each Fund. Under the terms of the agreement,
each of the Funds will pay a fee equal to the following annual percentages of
average net assets:
ASSETS IN
FOR THE FIRST EXCESS OF
$100,000,000 $100,000,000
PER FUND PER FUND
-------- --------
PRIMECAP Odyssey Stock Fund ................... 0.60% 0.55%
PRIMECAP Odyssey Growth Fund .................. 0.60% 0.55%
PRIMECAP Odyssey Aggressive Growth Fund ....... 0.60% 0.55%

The Bank of New York Mellon Corporation serves as the Funds' custodian. U.S.
Bancorp Fund Services, LLC ("USBFS") serves as the administrator, fund
accountant, and transfer agent to the Funds. Quasar Distributors, LLC, an
affiliate of USBFS, serves as the Funds' distributor.

(7) OTHER AFFILIATES

Certain of the Funds' investments are in companies that are considered
affiliated companies of a Fund because the Fund owns more than 5% of the
outstanding voting securities of the company. Transactions during the period in
securities of these companies were as follows:

PRIMECAP ODYSSEY GROWTH FUND

MARKET PROCEEDS MARKET
VALUE AS OF FROM VALUE AT
OCTOBER 31, PURCHASES SECURITIES DIVIDEND REALIZED APRIL 30,
Common Stock 2009 at Cost Sold Income Gain (Loss) 2010
- -----------------------------------------------------------------------------------------------
Conceptus, Inc. ... 20,202,572 9,891,971 -- -- -- 31,620,330
Immunogen, Inc. ... -- 36,919,843 -- -- -- 46,577,000
Total ............. $20,202,572 $46,811,814 -- -- -- $78,197,330

PRIMECAP ODYSSEY AGGRESSIVE GROWTH FUND

MARKET PROCEEDS MARKET
VALUE AS OF FROM VALUE AT
OCTOBER 31, PURCHASES SECURITIES DIVIDEND REALIZED APRIL 30,
Common Stock 2009 at Cost Sold Income Gain (Loss) 2010
- -----------------------------------------------------------------------------------------------
Immunogen, Inc. ... 3,928,368 18,277,027 -- -- -- 29,180,114
Total ............. $ 3,928,368 $18,277,027 -- -- -- $29,180,114

NOTES TO FINANCIAL STATEMENTS
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
FOR THE SIX MONTHS ENDED APRIL 30, 2010 (UNAUDITED) - CONTINUED

(8) SUBSEQUENT EVENTS

In preparing the financial statements as of April 30, 2010, management
considered the impact of subsequent events for potential recognition or
disclosure in these financial statements.

(9) ACCOUNTING PRONOUNCEMENTS

In January 2010, the Financial Accounting Standards Board issued Accounting
Standards Update (ASU) No. 2010-6, Fair Value Measurements and Disclosures
(Topic 820): Improving Disclosures and Fair Value Measurements. ASU No. 2010-6
enhances and clarifies existing fair value measurement disclosure requirements
and is effective for interim and annual periods beginning after December 15,
2009. The Funds are currently evaluating the impact, if any, of applying the
provisions of ASU No. 2010-6.

ADDITIONAL INFORMATION
PRIMECAP ODYSSEY FUNDS
----------------------------------------------------------------
(UNAUDITED)

PROXY VOTING PROCEDURES

The Investment Advisor votes proxies relating to portfolio securities in
accordance with procedures that have been approved by the Trust's board of
trustees. You may obtain a description of these procedures, free of charge, by
calling toll-free 1-800-729-2307. This information is also available through the
Securities and Exchange Commission's ("SEC") website at http://www.sec.gov.

PROXY VOTING RECORD

Information regarding how the Funds voted proxies relating to the portfolio
securities during the most recent 12-month period ended June 30 is available
without charge, upon request, by calling toll-free 1-800-729-2307. This
information is also available through the SEC's website at http:// www.sec.gov.

FORM N-Q DISCLOSURE

The Trust files its complete schedules of portfolio holdings with the SEC for
the first and third quarters of each fiscal year on Form N-Q. The Trust's Form
N-Q is available on the SEC's website at http://www.sec.gov. The Trust's Form
N-Q may be reviewed and copied at the Commission's Public Reference Room in
Washington, DC, and information on the operation of the Public Reference Room
may be obtained by calling 1-800-SEC-0330. This information is also available,
without charge, by calling toll-free 1-800-729-2307.

MANAGEMENT
PRIMECAP ODYSSEY FUNDS
----------------------------------------------------------------
(UNAUDITED)

PORTFOLIO MANAGERS

PRIMECAP Management Company has five portfolio managers who together have more
than 170 years of investment experience. Each of these five individuals manages
a portion of the PRIMECAP Odyssey Stock Fund and the PRIMECAP Odyssey Growth
Fund. The PRIMECAP Odyssey Aggressive Growth Fund is primarily managed by
Messrs. Schow, Kolokotrones, Fried, and Mordecai. A small portion of each Fund's
assets may be managed by individuals in the Investment Advisor's research
department. The portfolio managers primarily responsible for overseeing the
Funds' investments are:

NAME YEARS OF EXPERIENCE
--------------------------------------------
Howard B. Schow 53
Mitchell J. Milias 45
Theo A. Kolokotrones 39
Joel P. Fried 24
Alfred W. Mordecai 12
--------------------------------------------

OFFICERS AND TRUSTEES

The Trust's officers, who administer the Funds' daily operations, are appointed
by the board of trustees. The trustees are responsible for the overall
management of the Trust, including establishing the Funds' policies and general
supervision and review of their investment activities. The Statement of
Additional Information includes additional information about the Trust's
trustees and is available, without charge, by calling 1-800-729-2307 or at the
Funds' web site at www.odysseyfunds.com.

Executive Officers. The table below sets forth certain information about each of
the Trust's executive officers.

MANAGEMENT
PRIMECAP ODYSSEY FUNDS
- --------------------------------------------------------------------------------
(UNAUDITED) - CONTINUED

POSITION(S) TERM OF OFFICE;
NAME, ADDRESS HELD LENGTH OF PRINCIPAL OCCUPATION(S)
(YEAR OF BIRTH) WITH TRUST TIME SERVED DURING PAST 5 YEARS
- ---------------------------------------------------------------------------------------------------
Joel P. Fried Co-Chief Indefinite; Executive Vice President, Director,
225 South Lake Ave., Executive Since 09/04 Portfolio Manager, and Principal
Suite 400, Pasadena, CA Officer and Trustee PRIMECAP Management Company
91101-3005
(1962)
- ---------------------------------------------------------------------------------------------------
David H. Van Slooten Chief Financial Indefinite; Executive Vice President, Portfolio
225 South Lake Ave., Officer and Since 06/04 Manager, Financial Analyst, and Principal
Suite 400, Pasadena, CA Secretary PRIMECAP Management Company
91101-3005
(1963) Chief Indefinite;
Administrative Since 02/09
Officer
- ---------------------------------------------------------------------------------------------------
Karen Chen Vice President Indefinite; Chief Compliance Officer, Director of
225 South Lake Ave., of Compliance Since 10/04 Compliance and Reporting, PRIMECAP
Suite 400, Pasadena, CA and Chief Management Company
91101-3005 Compliance
(1973) Officer and
AML Officer
- ---------------------------------------------------------------------------------------------------

"INDEPENDENT" TRUSTEES. The table below sets forth certain information about each of the trustees of
the Trust who is not an "interested person" of the Trust as defined in the 1940 Act ("Independent
Trustees").

NUMBER OF
TERM OF PORTFOLIOS OTHER
POSITION(S) OFFICE; IN FUND DIRECTOR-
NAME, ADDRESS HELD LENGTH OF PRINCIPAL OCCUPATION(S) COMPLEX BY SHIPS HELD
(YEAR OF BIRTH) WITH TRUST TIME SERVED DURING PAST 5 YEARS TRUSTEE(1) BY TRUSTEE
- ---------------------------------------------------------------------------------------------------
Benjamin F. Hammon Chairman Indefinite; Retired; Director, 3 None
225 South Lake Ave., of the Since 09/04 Institutional Equity
Suite 400, Pasadena, CA Board and Sales, Salomon Smith
91101-3005 Trustee Barney Inc. (1963-1998)
(1935)
- ---------------------------------------------------------------------------------------------------
Wayne H. Smith Chairman Indefinite; Retired; President, 3 None
225 South Lake Ave., of the Audit Since 09/04 Wayne H. Smith
Suite 400, Pasadena, CA Committee Consulting, Inc. (2002-
91101-3005 and Trustee 2007); Vice President,
(1941) Financial Services, Avery
Dennison Corporation
(2001-2002); Vice
President, Financial
Services, and Treasurer,
Avery Dennison
Corporation (1999-2001)
- ---------------------------------------------------------------------------------------------------

Management
PRIMECAP Odyssey Funds
- --------------------------------------------------------------------------------
(Unaudited) - continued

NUMBER OF
TERM OF PORTFOLIOS OTHER
POSITION(S) OFFICE; IN FUND DIRECTOR-
NAME, ADDRESS HELD LENGTH OF PRINCIPAL OCCUPATION(S) COMPLEX BY SHIPS HELD
(YEAR OF BIRTH) WITH TRUST TIME SERVED DURING PAST 5 YEARS TRUSTEE(1) BY TRUSTEE
- ------------------------------------------------------------------------------------------------------
Joseph G. Uzelac Trustee Indefinite; Retired; Managing 3 None
225 South Lake Ave., Since 10/07 Director, Lehman
Suite 400, Pasadena, CA Brothers Global
91101-3005 Investment Bank
(1944) (1988-2007)
- ------------------------------------------------------------------------------------------------------
Elizabeth D. Obershaw Trustee Indefinite; Managing Director, 3 None
225 South Lake Ave., Since 06/08 Horsley Bridge
Suite 400, Pasadena, CA Partners, a California-
91101-3005 based investment advisor
(1960) (2007-present); Vice
President and
Chief Investment
Officer, Hewlett-Packard
Company (1991-2007);
Hewlett-Packard
Company (1983-1991)
- ------------------------------------------------------------------------------------------------------

(1) Fund Complex includes any funds, series of funds, or trusts that share the same advisor or that hold
themselves out to investors as related companies.

"INTERESTED" TRUSTEES. The table below sets forth certain information about each of the trustees of
the Trust who is an "interested person" of the Trust as defined by the 1940 Act.

(1) Mr. Fried is an "interested person" of the Trust, as defined by the 1940
Act, because of his employ- ment with PRIMECAP Management Company, the
investment advisor to the Trust.

(2) Fund Complex includes any funds, series of funds, or trusts that share the
same advisor or that hold themselves out to investors as related companies.

This page intentionally left blank.

Investment Advisor
PRIMECAP MANAGEMENT COMPANY
225 South Lake Avenue, Suite 400
Pasadena, California 91101

Distributor
QUASAR DISTRIBUTORS, LLC
615 East Michigan Street, 4th Floor
Milwaukee, Wisconsin 53202

Custodian
THE BANK OF NEW YORK MELLON CORPORATION
One Wall Street
New York, New York 10286

Transfer Agent
U.S. BANCORP FUND SERVICES, LLC
615 East Michigan Street, 3rd Floor
Milwaukee, Wisconsin 53202

Administrator
U.S. BANCORP FUND SERVICES, LLC
2020 East Financial Way, Suite 100
Glendora, California 91741

Legal Counsel
BINGHAM McCUTCHEN LLP
355 South Grand Avenue, Suite 4400
Los Angeles, California 90071

Independent Registered Public Accounting Firm
PRICEWATERHOUSECOOPERS LLP
Three Embarcadero Center
San Francisco, California 94111

THIS REPORT IS INTENDED FOR THE SHAREHOLDERS OF THE PRIMECAP ODYSSEY FUNDS AND
MAY NOT BE USED AS SALES LITERATURE UNLESS PRECEDED OR ACCOMPANIED BY A CURRENT
PROSPECTUS.

PAST PERFORMANCE RESULTS SHOWN IN THIS REPORT SHOULD NOT BE CONSIDERED A
REPRESENTATION OF FUTURE PERFORMANCE. SHARE PRICE AND RETURNS WILL FLUCTUATE SO
THAT SHARES, WHEN REDEEMED, MAY BE WORTH MORE OR LESS THAN THEIR ORIGINAL COST.
STATEMENTS AND OTHER INFORMATION HEREIN ARE DATED AND ARE SUBJECT TO CHANGE.

PRIMECAP, PRIMECAP ODYSSEY, AND THE PRIMECAP ODYSSEY LOGO ARE TRADEMARKS OF
PRIMECAP MANAGEMENT COMPANY.

ITEM 2. CODE OF ETHICS.

Not applicable for semi-annual reports.

ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

Not applicable for semi-annual reports.

ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

Not applicable for semi-annual reports.

ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS.

Not applicable to registrants who are not listed issuers (as defined in Rule
10A-3 under the Securities Exchange Act of 1934).

ITEM 6. INVESTMENTS.

Schedule of Investments is included as part of the report to shareholders filed
under Item 1 of this Form.

ITEM 7. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED-END
MANAGEMENT INVESTMENT COMPANIES.

Not applicable to open-end investment companies.

ITEM 8. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable to open-end investment companies.

ITEM 9. PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT INVESTMENT
COMPANY AND AFFILIATED PURCHASERS.

Not applicable to open-end investment companies.

ITEM 10. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

There have been no material changes to the procedures by which shareholders may
recommend nominees to the registrant's board of directors/trustees.

ITEM 11. CONTROLS AND PROCEDURES.

(a) The Registrant's Co-Chief Executive Officers and Chief Financial Officer
have reviewed the Registrant's disclosure controls and procedures (as
defined in Rule 30a-3(c) under the Investment Company Act of 1940 (the
"Act")) as of a date within 90 days of the filing of this report, as
required by Rule 30a-3(b) under the Act and Rules 13a-15(b) or 15d-15(b)
under the Securities Exchange Act of 1934. Based on their review, such
officers have concluded that the disclosure controls and procedures are
effective in ensuring that information required to be disclosed in this
report is appropriately recorded, processed, summarized and reported and
made known to them by others within the Registrant and by the Registrant's
service provider.

(b) There were no changes in the Registrant's internal control over financial
reporting (as defined in Rule 30a-3(d) under the Act) that occurred during
the second fiscal quarter of the period covered by this report that has
materially affected, or is reasonably likely to materially affect, the
Registrant's internal control over financial reporting.

ITEM 12. EXHIBITS.

(a) (1) ANY CODE OF ETHICS OR AMENDMENT THERETO, THAT IS THE SUBJECT OF THE
DISCLOSURE REQUIRED BY ITEM 2, TO THE EXTENT THAT THE REGISTRANT INTENDS TO
SATISFY ITEM 2 REQUIREMENTS THROUGH FILING AN EXHIBIT. NOT APPLICABLE.

(2) A SEPARATE CERTIFICATION FOR EACH PRINCIPAL EXECUTIVE AND PRINCIPAL
FINANCIAL OFFICER PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF
2002. FILED HEREWITH.

(3) ANY WRITTEN SOLICITATION TO PURCHASE SECURITIES UNDER RULE 23C-1 UNDER
THE ACT SENT OR GIVEN DURING THE PERIOD COVERED BY THE REPORT BY OR ON
BEHALF OF THE REGISTRANT TO 10 OR MORE PERSONS. NOT APPLICABLE TO
OPEN-END INVESTMENT COMPANIES.

(b) CERTIFICATIONS PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002.
FURNISHED HEREWITH.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, the registrant has duly caused this report to be
signed on its behalf by the undersigned, thereunto duly authorized.

PRIMECAP Odyssey Funds

By /s/ Joel P. Fried
Joel P. Fried, Co-Chief Executive Officer

Date June 30, 2010

By /s/ Howard B. Schow
Howard B. Schow, Co-Chief Executive Officer

Date June 30, 2010

By /s/ Theo A. Kolokotrones
Theo A. Kolokotrones, Co-Chief Executive Officer

Date June 30, 2010

Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, this report has been signed below by the
following persons on behalf of the registrant and in the capacities and on the
dates indicated.

By /s/ Joel P. Fried
Joel P. Fried, Co-Chief Executive Officer

Date June 30, 2010

By /s/ Howard B. Schow
Howard B. Schow, Co-Chief Executive Officer

Date June 30, 2010

By /s/ Theo A. Kolokotrones
Theo A. Kolokotrones, Co-Chief Executive Officer

Date June 30, 2010

By /s/ David H. Van Slooten
David H. Van Slooten, Chief Financial Officer

Date June 30, 2010

PRINT THE NAME AND TITLE OF EACH SIGNING OFFICER UNDER HIS OR HER SIGNATURE.