SECURITIES AND EXCHANGE COMMISSION

                              Washington, DC 20549
                                 ---------------

                                    FORM 10-Q


[X] QUARTERLY REPORT UNDER SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE
                                   ACT OF 1934

                For the Quarterly Period Ended September 30, 1997

                                       OR

[ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
                              EXCHANGE ACT OF 1934
                        For the transition period from to

                        Commission file number 000-19392

                              DIANON SYSTEMS, INC.
             (exact name of registrant as specified in its charter)

                     Delaware                            06-1128081
           (State of incorporation)           (IRS Employer Identification No.)

        200 Watson Blvd, Stratford, CT                        06497
  (Address of principal executive offices)                 (zip code)

       Registrant's telephone number, including area code: (203) 381-4000

                                 NOT APPLICABLE
              (Former name, former address and former fiscal year,
                          if changed since last report)

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the  preceding 12 months (or for such  shorter  period that the  registrant  was
required  to file  such  reports)  and  (2)  has  been  subject  to such  filing
requirements for the past 90 days.

                                                                Yes X No_

The  number  of  shares  of the  registrant's  Common  Stock,  $.01  par  value,
outstanding on November 7, 1997 was 6,494,136 shares.

                      Exhibit Index on page 15 of 41 pages





                              DIANON SYSTEMS, INC.
                                AND SUBSIDIARIES
                                      INDEX




PART I FINANCIAL INFORMATION                                           PAGE NO.
- ----------------------------                                           --------

                                                                     
Item 1.    FINANCIAL STATEMENTS

           Consolidated Balance Sheets as of
           September 30, 1997 and December 31, 1996.                       3

           Consolidated Statements of Operations for
           the three month and nine month periods ended
           September 30, 1997 and 1996.                                    4

           Consolidated Statements of Stockholders'
           Equity for the nine months ended
           September 30, 1997 and 1996.                                    5

           Consolidated Statements of Cash Flows for
           the nine months ended September 30, 1997 and 1996.              6

           Notes to Consolidated Financial Statements.                     7

Item 2.    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
           FINANCIAL CONDITION AND RESULTS OF OPERATIONS                   8-12


PART II  OTHER INFORMATION
- --------------------------

Item 6.    EXHIBITS AND REPORTS ON  FORM 8-K                               13

Signatures                                                                 14

Exhibit Index                                                              15







                              DIANON SYSTEMS, INC.
                           CONSOLIDATED BALANCE SHEETS



                                                                                     SEPT. 30,     DECEMBER 31,
                                                                                       1997            1996
                                                                                  -----------------------------
                                                                                   (UNAUDITED)
                                    ASSETS
CURRENT ASSETS:
                                                                                                     
     Cash and cash equivalents                                                    $ 11,150,602    $  7,488,590
     Accounts receivable, net of allowances of $1,085,076 and
        $1,056,920, respectively                                                    14,506,148      15,426,221
     Prepaid expenses and employee advances                                          1,069,257       1,189,139
     Prepaid and refundable income taxes                                               150,233         329,371
     Inventory                                                                         765,544         662,567
     Deferred income tax asset                                                         677,277         677,277
                                                                                  -----------------------------
        Total current assets                                                        28,319,061      25,773,165
                                                                                  -----------------------------
PROPERTY AND EQUIPMENT, at cost
     Laboratory and office equipment                                                13,244,119      12,233,989
     Leasehold improvements                                                          3,832,539       3,612,198
        Less - accumulated depreciation and amortization                           (10,364,768)     (8,606,176)
                                                                                  -----------------------------
                                                                                     6,711,890       7,240,011
                                                                                  -----------------------------

INTANGIBLE ASSETS, net of accumulated amortization of
        $3,153,499 and $2,991,286, respectively                                        442,100         604,131
DEFERRED INCOME TAX ASSET                                                              458,465         458,465
OTHER ASSETS                                                                           327,443         459,696
                                                                                  =============================
        TOTAL ASSETS                                                              $ 36,258,959    $ 34,535,650
                                                                                  =============================

                  LIABILITIES AND STOCKHOLDERS' EQUITY
CURRENT LIABILITIES:
     Accounts payable                                                             $    808,720    $  2,123,661
     Accrued employee bonuses, commissions and payroll                               2,022,468       1,504,430
     Accrued employee stock purchase plan                                              963,309         549,540
     Current portion of capitalized lease obligations                                   40,854          26,107
     Current portion of note payable                                                        --         650,154
     Other accrued expenses                                                          4,640,465       2,861,268
                                                                                  -----------------------------
        Total current liabilities                                                    8,475,816       7,715,160
                                                                                  -----------------------------
LONG-TERM PORTION OF CAPITALIZED LEASE OBLIGATIONS                                     115,876          69,611
DEFERRED INCOME TAX LIABILITY                                                          201,951         201,951
                                                                                  -----------------------------
        Total liabilities                                                            8,793,643       7,986,722
                                                                                  -----------------------------
STOCKHOLDERS' EQUITY
     Common  stock,  par value  $.01 per share, 20,000,000 shares
        authorized, 6,782,894 and 6,712,774  shares issued and
        outstanding at September 30, 1997 and December 31, 1996,
        respectively                                                                    67,829          67,128
     Additional paid-in capital                                                     28,270,841      27,965,560
     Accumulated earnings/(deficit)                                                  1,714,347        (554,317)
     Common stock held in treasury, at cost - 310,814 and 117,196
        shares at September 30, 1997 and December 31, 1996, respectively            (2,587,701)       (929,443)
                                                                                  -----------------------------
        Total stockholders' equity                                                  27,465,316      26,548,928
                                                                                  =============================
        TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY                                $ 36,258,959    $ 34,535,650
                                                                                  =============================
                                         The accompanying notes to consolidated financial
                                     statements are an integral part of these balance sheets.










                                       DIANON SYSTEMS, INC.
                                CONSOLIDATED STATEMENTS OF OPERATIONS
                         FOR THE THREE MONTH AND NINE MONTH PERIODS ENDED
                                   SEPTEMBER 30, 1997 AND 1996
                                             (UNAUDITED)






                                                                         THREE MONTHS ENDED                    NINE MONTHS ENDED
                                                                            SEPTEMBER 30,                         SEPTEMBER 30,
                                                                      1997               1996               1997              1996
                                                               ---------------------------------------------------------------------
                                                                                                                     
NET REVENUES                                                     $14,512,373          $13,863,408       $46,169,947      $39,956,557

COST OF GOODS                                                      7,621,207            6,799,712        23,376,222       19,419,522
                                                               ---------------------------------------------------------------------
     Gross Profit                                                  6,891,166            7,063,696        22,793,725       20,537,035

SELLING, GENERAL AND
  ADMINISTRATIVE EXPENSES                                          5,224,120            5,222,176        17,822,103       15,891,036
RESEARCH & DEVELOPMENT
  EXPENSES                                                           381,681              722,157         1,350,246        2,304,239
                                                               ---------------------------------------------------------------------

     Income from Operations                                        1,285,365            1,119,363         3,621,376        2,341,760

INTEREST INCOME                                                      158,622               50,573           382,749          280,365

INTEREST EXPENSE                                                       5,192               18,038            24,013           62,779
                                                               ---------------------------------------------------------------------

     Income Before Provision for Income Taxes                      1,438,795            1,151,898         3,980,112        2,559,346

PROVISION FOR INCOME TAXES                                           618,682              495,316         1,711,448        1,100,519
                                                               ---------------------------------------------------------------------

   Net Income                                                     $  820,113           $  656,582       $ 2,268,664      $ 1,458,827
                                                               =====================================================================

Weighted Average Shares Outstanding                                6,835,636            6,295,106         6,844,341        6,228,925
                                                               ---------------------------------------------------------------------

Primary and Fully Diluted Earnings Per Share                           $0.12                $0.10             $0.33            $0.23
                                                               =====================================================================


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












                                                                 DIANON SYSTEMS, INC.
                                                    CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
                                                 FOR THE NINE MONTHS ENDED SEPTEMBER 30, 1997 AND 1996
                                                                      (UNAUDITED)



                                                                                Common Stock  Common Stock
                                                                     Additional Acquired for  Acquired for  Shareholder
                                    Common Stock        Paid-In      Earnings/   Treasury,     Treasury,       Note
                                 Shares       Amount    Capital      (Deficit)    Shares        at Cost      Receivable    Total
                                ----------------------------------------------------------------------------------------------------
                                                                                               
BALANCE, December 31, 1995       6,311,451    $63,115   $26,609,657  ($2,724,433)  (50,000)  ($ 200,000)  ($296,000)  $23,452,339
  Stock options exercised           12,847        128        58,454           --        --           --         --        58,582
  Common stock acquired for 
     treasury                           --         --            --           --  (371,000)  (2,083,078)        --    (2,083,078)
  Net Income                            --         --            --    1,458,827       --           --          --     1,458,827
                                ====================================================================================================
BALANCE, September 30, 1996      6,324,298    $63,243   $26,668,111  ($1,265,606) (421,000) ($2,283,078) ($296,000)  $22,886,670
                                ====================================================================================================

BALANCE, December 31, 1996       6,712,774    $67,128   $27,965,560  ($  554,317) (117,196) ($  929,443)   $    --   $26,548,928
  Stock options exercised           44,503        445       212,011           --        --           --         --       212,456
  Employee stock purchase plan
     options exercised                  --         --      (127,753)          --    33,382      277,772         --       150,019
     Stock grants                   25,617        256       221,023           --       --           --          --       221,279
     Common stock acquired for
       treasury                         --         --            --           --  (227,000)  (1,936,030)        --    (1,936,030)
     Net Income                         --         --            --    2,268,66        --           --          --     2,268,664
                                ====================================================================================================
BALANCE, September 30, 1997      6,782,894    $67,829   $28,270,841   $1,714,347  (310,814) ($2,587,701)   $    --   $27,465,316
                                ====================================================================================================



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
















                                                  DIANON SYSTEMS, INC.
                                          CONSOLIDATED STATEMENTS OF CASH FLOWS
                                  FOR THE NINE MONTHS ENDED SEPTEMBER 30, 1997 AND 1996
                                                       (UNAUDITED)



                                                                                                     SEPTEMBER 30,
                                                                                            -------------------------------
        CASH FLOWS FROM OPERATING ACTIVITIES:                                                    1997               1996
                                                                                            -------------------------------
                                                                                                                 
            Net income                                                                       $ 2,268,664        $1,458,827
        Adjustments to reconcile net income to net
            cash provided by (used in) operations -
             Non-cash charges
                 Depreciation and amortization                                                 2,216,659         1,690,047
                 Stock compensation expense                                                      221,279                --
                 Loss on the disposal of fixed assets                                             40,914            19,337
                 Investment write-down                                                                --            61,846
        Changes in other current assets and liabilities
             Decrease (increase) in accounts receivable                                          920,073        (2,836,940)
             Decrease (increase) in prepaid expenses and
                 employee advances                                                               299,020          (322,668)
             (Increase) in inventory                                                            (102,977)          (79,296)
             Decrease (increase) in other assets                                                 112,361            (3,788)
             Increase in accounts payable and accrued liabilities                              1,433,843           884,617
                                                                                            -------------------------------
                           Net cash provided by operating activities                           7,409,836           871,982
                                                                                            -------------------------------

        CASH FLOWS FROM INVESTING ACTIVITIES:
             Capital expenditures                                                             (1,650,368)       (3,315,215)
             Proceeds from the sale of stock held for investment                                   9,064            73,661
             Proceeds from the disposal of fixed assets                                               --            7,500
                                                                                            -------------------------------
             Net cash (used in) investing activities                                          (1,641,304)       (3,234,054)
                                                                                            -------------------------------

        CASH FLOWS FROM FINANCING ACTIVITIES:
             Repayments of note payable                                                         (650,154)         (681,790)
             Borrowings (repayments) of capitalized lease obligations, net                       117,189            39,406
             Purchase of common stock acquired for treasury                                   (1,936,030)       (2,083,078)
             Stock options exercised                                                             212,456            58,582
             Employee stock purchase plan options exercised                                      150,019                --
                                                                                            -------------------------------
                         Net cash (used in) financing activities                              (2,106,520)       (2,666,880)
                                                                                            -------------------------------
                         Net increase (decrease) in cash and cash equivalents                  3,662,012        (5,028,952)

        CASH AND CASH EQUIVALENTS, beginning of period                                          7,488,590       10,990,231
                                                                                            -------------------------------
        CASH AND CASH EQUIVALENTS, end of period                                              $11,150,602       $5,961,279
                                                                                            ===============================

        Supplemental cash flow disclosures:
        Cash paid during the period:
                 Interest                                                                         $24,795           $63,174
                 Income Taxes                                                                   1,475,089         1,299,005


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







                              DIANON SYSTEMS, INC.
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

1.   THE COMPANY - The consolidated  balance sheet as of September 30, 1997, the
     related consolidated  statements of operations for the three and nine month
     periods  ended  September  30,  1997 and  1996,  the  related  consolidated
     statements  of cash flow for the nine months ended  September  30, 1997 and
     1996, and the related  consolidated  statements of stockholders' equity for
     the nine months  ended  September  30, 1997 and 1996 have been  prepared by
     DIANON  Systems,  Inc. (the  "Company")  without  audit.  In the opinion of
     management,  all  adjustments  necessary  to present  fairly the  financial
     position,  results of  operations  and cash flows at September 30, 1997 and
     1996 have been made. During the interim periods reported on, the accounting
     policies  followed are in conformity  with  generally  accepted  accounting
     principles  and are  consistent  with those applied for annual  periods and
     described  in the  Company's  annual  report  filed on Form  10-K  with the
     Securities and Exchange Commission on March 31, 1997 (the "Annual Report").

     Certain information and footnote disclosures normally included in financial
     statements  prepared  in  accordance  with  generally  accepted  accounting
     principles  have been  omitted.  It is  suggested  that these  consolidated
     financial  statements be read in conjunction with the financial  statements
     included in the  Company's  Annual  Report for the year ended  December 31,
     1996.  The results of operations  for the nine months ending  September 30,
     1997 and 1996 are not necessarily  indicative of the operating  results for
     the full years.

2.   DESCRIPTIVE  ANALYSIS - The descriptive  analysis contained herein compares
     the financial results of the first nine months, and the three months, ended
     September 30 for the years 1997 and 1996. To accommodate  the comparison of
     pertinent financial  information the following terms will be used to denote
     the respective periods:

     "First Nine Months 1997" - nine months ended September 30, 1997 "First Nine
     Months 1996" - nine months ended September 30, 1996

     "Third Quarter 1997" - three months ended September 30, 1997 "Third Quarter
     1996" - three months ended September 30, 1996

3.   IMPACT OF  ACCOUNTING  PRONOUNCEMENTS,  NOT YET  ADOPTED  BY THE  COMPANY -
     Earnings Per Share  ("EPS"):  In February  1997,  the Financial  Accounting
     Standards  Board issued SFAS No. 128,  "Earnings Per Share," which requires
     public  companies  to present  basic EPS and, if  applicable,  diluted EPS,
     instead of primary and diluted EPS. Basic EPS is calculated by dividing the
     net income by the weighted  average  number of shares  outstanding  for the
     period, without consideration for common stock equivalents.  Diluted EPS is
     computed similarly to fully diluted EPS under the provisions of APB Opinion
     No. 15.  Revision of the EPS standard had two  objectives - to simplify the
     EPS  calculation  and to make the EPS  standard  applicable  to US entities
     comparable to the standard of most other countries and to the international
     standard,  which was also recently  revised.  SFAS No. 128 is effective for
     financial statements issued for periods ending after December 15, 1997. The
     Company's  basic  and  diluted  EPS  (which  are not yet  reflected  in the
     consolidated  financial  statements included herein because the Company has
     not yet adopted SFAS No. 128) are stated below:



                      Three Months   Three Months    Nine Months    Nine Months
                         Ended          Ended          Ended           Ended
                      September 30,  September 30,  September 30,  September 30,
                          1997            1996           1997          1996
                          ----            ----           ----          ----
                                                            
        Basic EPS        $0.13           $0.11          $0.35          $.25
        Diluted EPS      $0.12           $0.10          $0.33          $.23










                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                       CONDITION AND RESULTS OF OPERATIONS
                  NINE MONTHS ENDED SEPTEMBER 30, 1997 AND 1996
                                   (UNAUDITED)


RESULTS OF OPERATIONS
- ---------------------

      O    NET REVENUES

Net revenues were $46.2  million  during the First Nine Months 1997, an increase
of $6.2 million or 16% from the First Nine Months 1996.  Increased revenues were
attributable to increased market penetration by the Company's anatomic pathology
testing  services.  The increase in anatomic  pathology  testing services in the
First Nine  Months  1997 over the  comparable  period of 1996 was offset to some
extent by a decline in reimbursements in clinical chemistry and esoteric testing
services.

Net revenues  were $14.5  million  during the Third Quarter 1997, an increase of
$649,000 or 5% from the Third Quarter 1996. Increased revenues were attributable
to increased  market  penetration by the Company's  anatomic  pathology  testing
services.

      O    COST OF GOODS

Cost of goods,  which  consists  primarily  of  salaries  and wages,  laboratory
supplies,  outside services,  logistics  (primarily shipping and handling),  and
depreciation  expense,  was $23.4 million  during the First Nine Months 1997, an
increase of $4.0  million or 20% from the First Nine Months  1996.  Salaries and
wages were $8.0  million in the First Nine  Months  1997,  an  increase  of $1.9
million or 30% from the First Nine Months 1996.  This  increase was  principally
due to  increased  laboratory  and  physician  employment  incurred  to  support
increased  anatomic  pathology testing services.  Laboratory  supplies were $4.1
million  for the First  Nine  Months  ended 1997 and 1996.  Laboratory  supplies
decreased  to 8.9% of net  revenues  in the First Nine Months 1997 from 10.2% in
the First Nine Months 1996.  This decrease was the result of cost  efficiencies.
Logistics  were $4.5 million in the First Nine Months 1997,  an increase of $1.5
million or 48% from the First Nine Months 1996.  The increase in logistic  costs
was principally due to supporting new anatomic pathology testing services.  As a
percentage of net revenues, cost of goods increased to 51% during the First Nine
Months 1997 from 49% during the First Nine Months 1996.

Cost of goods was $7.6 million  during the Third  Quarter  1997,  an increase of
$821,000 or 12% from the Third  Quarter  1996.  As a percentage of net revenues,
cost of goods  increased to 53% in the Third  Quarter 1997 from 49% in the Third
Quarter 1996.

      O    GROSS PROFIT

Gross profits were $22.8 million  during the First Nine Months 1997, an increase
of $2.3  million or 11% from the First Nine Months  1996.  The  Company's  gross
profit  margin  decreased  to 49% in the First Nine  Months 1997 from 51% in the
First Nine  Months  1996.  The  decrease in gross  profit  margin was due to the
continued  erosion of the average  unit price  reimbursed  for certain  clinical
chemistry and esoteric  testing  services and the higher costs  associated  with
providing anatomic pathology testing services.

Gross  profits were $6.9 million  during the Third  Quarter  1997, a decrease of
$173,000 or 2% from the Third  Quarter 1996.  The Company's  gross profit margin
decreased to 47% in the Third  Quarter 1997 from 51% in the Third  Quarter 1996.
The  decrease  in  gross  profit  margin  was  partly  due  to  the  decline  in
reimbursements  for certain clinical chemistry and esoteric testing services and
the higher costs associated with providing anatomic pathology testing services.




The clinical  laboratory  industry,  which includes both clinical  chemistry and
anatomic pathology,  has seen steady downward pressure on prices exerted by both
government and private third party payors. A reduction in  reimbursement  rates,
particularly  by Medicare,  has  generally  decreased the average unit price for
most of the  Company's  clinical  chemistry  services each year. In keeping with
this trend,  as part of the  Omnibus  Budget  Reconciliation  Act of 1993 ("OBRA
`93"),  Congress  reduced over time the national cap on Medicare  laboratory fee
schedules.  This  national  cap has been lowered each year and is now 76% of the
national  median.  Under  the  provisions  of the  Balanced  Budget  Act of 1997
("BBA"),  the cap would be lowered  further to 74%  beginning in 1998.  OBRA `93
also eliminated the annual updates of Medicare  laboratory fee schedules for the
years 1994 and 1995.  After  updates of 3.2% in 1996 and  approximately  2.7% in
1997,  the terms of the BBA would  freeze fee  schedule  payments for the 1998 -
2002 period.

In addition,  payment for services such as those  provided by the Company is and
likely will  continue to be  affected by periodic  reevaluations  made by payors
concerning which services to reimburse and which to cease  reimbursing.  In some
cases,  government  payors  such as  Medicare  also may seek to recoup  payments
previously made for services determined not to be reimbursable.  Any such action
by payors would have an adverse affect on the Company's revenue and earnings.

The BBA does include the addition of coverage for a yearly  screening  pap smear
for Medicare beneficiaries at high risk of developing cervical or vaginal cancer
and for  beneficiaries  of  childbearing  age who had not had a negative test in
each of the  preceding  three  years,  effective  January  1,  1998;  as well as
coverage for annual prostate  cancer  screening,  including a  prostate-specific
antigen blood test, for  beneficiaries  over age 50, effective  January 1, 2000.
Although  most women of  childbearing  age and men under age 65 are not Medicare
beneficiaries,  the addition of Medicare  coverage for these tests could provide
additional revenues for the Company.

With respect to the Company's  tissue  testing  services,  which are  reimbursed
under the  physician  fee  schedules  rather than the  Medicare  laboratory  fee
schedules, the Medicare fees for these services also generally declined with the
implementation of the resource based relative value scale ("RBRVS") system which
went  into  effect  in 1992 and was  fully  phased  in by the end of  1996.  The
Medicare RBRVS payment for each service is calculated by  multiplying  the total
relative  value units  ("RVUs")  established  for the  services by a  conversion
factor that is set by law.  The number of RVUs  assigned  to each  service is in
turn calculated by adding three separate components,  including one representing
the  relative  work  values.  Although the  conversion  factor for  non-surgical
services,  including  pathology,  is  currently  $33.8454,  the BBA  includes  a
provision  that merges the three  existing  conversion  factors into one for all
types of services  provided.  This single factor will be $36.69 - an increase of
8.3% over the 1997 conversion factor applicable to pathology services.

There was an overall decrease of 5.7% between 1996 and 1997 in payments per RVUs
for pathology  services,  plus an additional  decrease in Connecticut due to the
Health  Care  Financing  Administration's  ("HCFA")  reduction  of the number of
different payment localities  recognized for RBRVS purposes. At the beginning of
1997, HCFA published  proposed  regulations which recalculate a key component of
the RBRVS fee schedule.  This  recalculation  would modify the practice  expense
RVUs to reflect  resource  consumption,  rather than the historical  charge data
used to establish the original practice expense RVUs. Overall,  HCFA's predicted
impact of this modification to reflect  resource-based  practice expense RVUs on
Medicare  income of  pathologists  is an increase  of 1%. Of course,  the actual
impact on  Medicare  pathology  revenues  would  depend on the mix of  pathology
services furnished.  Moreover,  under the BBA,  implementation of resource based
practice  expense RVUs will not begin until 1999, and will be phased in over the
period 1999 - 2002. In addition,  disclosure and  evaluation of the  methodology
used by HCFA to  support  its  proposal  will be  required.  In the past,  RBRVS
program  implementation  and modification has had the effect of reducing prices,
and thus the gross profit, of the Company.  Overall, the Company does not expect
projected future RBRVS adjustments to change this trend.

Other changes in government and other third-party payor  reimbursement which may
come about as a  consequence  of the enactment of current and future health care
reform or  deficit  reduction  measures  are  likely to  continue  the  downward
pressure on prices and make the market for  clinical  laboratory  services  more
competitive.






For example,  the BBA would revise the Medicare program  substantially to permit
beneficiaries to choose between traditional  fee-for-service Medicare as well as
several  non-traditional  Medicare  options,  including  managed  care plans and
provider-sponsored  organization  plans.  These  non-traditional  Medicare plans
would have considerable  discretion in determining  whether and how to cover and
reimburse  laboratory  services and also have  discretion to limit the number of
labs with which they deal.

The BBA also includes  provisions to implement  competitive  bidding for certain
Medicare  items and services,  including  laboratory  services,  on a three-site
demonstration  project  basis.  If later  adopted on a widespread  basis,  these
changes likely would have an adverse impact on the Company's revenues,  and thus
on its gross profit.

In addition, the BBA contains measures to establish  market-oriented  purchasing
for Medicare,  including  prospective  payment  systems for outpatient  hospital
services, home health care and nursing home care, and the use of global payments
and flexible  purchasing.  Although the details of these  measures are yet to be
finalized,  they probably would  increase  pressure on pricing in the laboratory
industry and may have an adverse impact on the Company's revenues.

Finally,  in recent months the federal  government has become more aggressive in
examining billing by laboratories, and in seeking repayments and even penalties,
based on how services were billed (e.g., the billing codes used),  regardless of
whether carriers had furnished clear guidance on this subject. The primary focus
of this initiative has been on hospital  laboratories,  and on routine  clinical
chemistry tests which provide only a small part of the Company's revenues. While
it is possible that this initiative could expand,  it is not possible to predict
whether  or in what  direction  this  might  occur.  The  Company  believes  its
practices  differ  materially  from  those  now  being  examined.   However,  no
assurances can be given that the  government  will not broaden its initiative to
focus on the type of  services  furnished  by the  Company  or,  if this were to
happen, on how much money, if any, the Company might have to pay.

Because of the uncertainties  about how the Medicare  developments such as those
described above will be implemented,  the Company currently is unable to predict
their ultimate impact on the laboratory  industry generally or on the Company in
particular.  Reforms  may also occur at the state  level as well as the  federal
level and, in addition,  changes are occurring in the marketplace as a result of
market pressures, as the number of patients covered by some form of managed care
is increasing.  In the past, the Company has offset a substantial portion of the
impact of price  decreases  and  coverage  changes  through the  achievement  of
economies of scale, more favorable  purchase  contracts and greater  operational
efficiencies. However, if price decreases (for example arising from the proposed
Medicare  changes  discussed  above) or coverage  changes were to be rapidly and
fully implemented,  or if the government were to seek any substantial repayments
or penalties  from the  Company,  such  developments  would be likely to have an
adverse  impact on gross  profits from the  Company's  testing  services  unless
management had an opportunity to mitigate such impact.

      O    SELLING, GENERAL AND ADMINISTRATIVE EXPENSES

Selling, general and administrative expenses were $17.8 million during the First
Nine Months 1997,  an increase of $1.9 million or 12% from the First Nine Months
1996.  As a percentage  of net  revenues,  selling,  general and  administrative
expenses  decreased  to 39% in the First Nine  Months 1997 from 40% in the First
Nine Months 1996.

Selling,  general and administrative expenses were $5.2 million during the Third
Quarter  1997 and the Third  Quarter  1996.  As a  percentage  of net  revenues,
selling,  general  and  administrative  expenses  decreased  to 36% in the Third
Quarter 1997 from 38% in the Third Quarter 1996.

Severance costs of approximately $259,000 were recorded in the First Nine Months
1997 compared with  $148,000  recorded in the First Nine Months 1996.  Severance
costs of approximately $100,000 were recorded in the Third Quarter 1997 compared
with $102,000 recorded in the Third Quarter 1996.





Investment write-downs of $62,000 were recorded in the First Nine Months 1996 to
write-down the investment,  held on the Company's balance sheet, in common stock
of a publicly  traded  company  to market  value as the loss in value was deemed
other than  temporary in accordance  with the Statement of Financial  Accounting
Standard  115,   "Accounting   for  Certain   Investments  on  Debt  and  Equity
Securities". No similar charges were recorded in the First Nine Months 1997. The
Company sold its remaining shares in the first quarter of 1997.

      O    RESEARCH AND DEVELOPMENT

Research  and  development  expenses  were $1.4 million in the First Nine Months
1997,  a decrease of $954,000 or 41% from the First Nine Months  1996.  Research
and development expenses include the costs of the review,  analysis and clinical
evaluation  of new  technologies.  This decrease in 1997 is primarily due to the
completion  in  1996  of the  major  one-time  expenditures  necessary  for  the
development of the new anatomic pathology services.

Research and  development  expenses  were  $382,000 in the Third Quarter 1997, a
decrease of $340,000 or 47% from the Third Quarter 1996.

      O    INTEREST INCOME

The  Company's  interest  income was $383,000 for the First Nine Months 1997, an
increase of $102,000 or 37% from the First Nine Months 1996. Interest income for
the First Nine Months 1997 was earned on an average  investment  of $9.4 million
compared  with $8.3 million in the First Nine Months 1996.  Interest  income was
$159,000 for the Third  Quarter  1997,  an increase of $108,000 or 214% from the
Third Quarter 1996.  Interest income for the Third Quarter 1997 was earned on an
average  investment  of $11.0  million  compared  with $5.4 million in the Third
Quarter 1996.

      O    INTEREST EXPENSE

Interest  expense  was $24,000  for the First Nine  Months  1997,  a decrease of
$39,000 or 62% from the First Nine Months 1996. The decrease in interest expense
was due to the on-going  pay-down of the $3.5 million term loan obtained in July
of 1993 which bears interest at 6% per year. Interest expense was $5,000 for the
Third Quarter 1997, a decrease of $13,000 or 71% from the Third Quarter 1996. As
of the end of the Third  Quarter  1997 this term loan has been  completely  paid
off.

      O    PROVISION FOR INCOME TAXES

Provision  for income tax  expense  was $1.7  million  for the First Nine Months
1997,  an  increase of  $611,000  or 56% from the First Nine  Months  1996.  The
effective  tax rate was 43%  during  both the First Nine  Months  1997 and 1996.
Provision  for income tax expense was $619,000 for the Third  Quarter  1997,  an
increase of $123,000 or 25% from the Third Quarter 1996.  The effective tax rate
was 43% during both the Third Quarter 1997 and 1996.

      O    NET INCOME

As a result of the  foregoing,  net income was $2.3  million  for the First Nine
Months 1997, an increase of $810,000 or 56% from the First Nine Months 1996. Net
income was $820,000  during the Third  Quarter  1997, an increase of $164,000 or
25% from the Third Quarter 1996.

LIQUIDITY AND CAPITAL RESOURCES
- -------------------------------

As of September  30, 1997,  the Company had total cash and cash  equivalents  of
approximately  $11.2  million of which  $10.5  million  was  invested  in a fund
holding U. S. Treasury securities with maturities of less than three months.

The Company had working  capital of $19.8 million at September 30, 1997 compared
to $18.1 million at December 31, 1996, and the working  capital ratio was 3.3 to
1 at September 30, 1997 compared to 3.4 to 1 at December 31, 1996.





Domestic trade receivables,  net, were $14.5 million as of September 30, 1997, a
decrease of $713,000 or 5% from  December 31, 1996.  The average  number of days
sales has  decreased  from 94 days for the month of December 1996 to 92 days for
the month of September 1997.

Capital  expenditures  during the First Nine Months 1997 were approximately $1.7
million compared to $3.3 million for the First Nine Months 1996.

As of September  30, 1997,  the Company had in its  treasury  310,814  shares of
Common Stock allocated for the Company's Employee Stock Purchase Plan at a total
cost of $2.6 million.  The Company plans to continue to repurchase  shares under
its previously authorized buyback program.

The Company  believes that cash flows from  operations as well as available cash
and cash  equivalents  are  adequate to fund the  Company's  operations  for the
foreseeable future.

RISK FACTORS; FORWARD LOOKING STATEMENTS
- --------

The  Management's  Discussion and Analysis  contain forward  looking  statements
regarding the  Company's  future plans,  objectives,  and expected  performance.
These  statements  are  based on  assumptions  that  the  Company  believes  are
reasonable,  but are subject to a wide range of risks and  uncertainties,  and a
number of factors could cause the Company's actual results to differ  materially
from those expressed in the forward-looking  statements referred to above. These
factors include,  among others,  the  uncertainties  in reimbursement  rates and
reimbursement  coverage of various tests sold by the Company to beneficiaries of
the Medicare  program;  the  possibility of being deemed to be not in compliance
with federal or state regulatory requirements; the uncertainties relating to the
ability of the Company to convince  physicians and/or managed care organizations
to use the Company as a provider of anatomic  pathology  testing  services;  the
ability of the Company to maintain superior quality relative to its competitors;
the ability of the Company to maintain its  hospital-based  business in light of
the  competitive  pressures  and  changes  occurring  in  hospital  health  care
delivery;  the  uncertainties  relating  to  states  erecting  barriers  to  the
performance  of  anatomic   national   laboratories;   competition   from  small
specialized  laboratories  and  well  established  local  pathologists;  and the
uncertainties which would arise if integrated delivery systems closed to outside
providers emerged as the dominant form of health care delivery.






PART II OTHER INFORMATION


Item 6      EXHIBITS AND REPORTS ON FORM 8-K
            



a       Exhibits

          
(3.3)    Restated  By-Laws of the Company,  as amended  through February 2, 1997
         (filed herewith).

(10.42)  Non-Compete  Agreement  dated September 3, 1997, by  the Registrant and
         Vernon L. Wells (filed herewith).

(10.43)  Severance  Agreement  dated  September 15, 1997, by  the Registrant and
         Robert C. Verfurth (filed herewith).

(11.1)   Statement regarding  computation of per  share earnings is not required
         because  the relevant  computation  can be determined from the material
         contained in the Financial Statements included herein.

(27.1)   Financial Data Schedule (filed herewith).

  b     Report on Form 8-K. No reports on Form 8-K were filed during the quarter
        ended September 30, 1997.










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


                                          DIANON Systems, Inc.



                      November 13, 1997   /S/ KEVIN C. JOHNSON
                                          --------------------
                                      By: Kevin C. Johnson
                                          President and
                                          Chief Executive Officer
                                          (Principal Executive Officer)





                      November 13, 1997  /S/ DAVID R. SCHREIBER
                                         ----------------------
                                         By: David R. Schreiber
                                             Senior Vice President, Finance and
                                             Chief Financial Officer
                                             (Principal Financial and
                                             Accounting Officer)








                                  EXHIBIT INDEX




                                                                                                                   PAGE NO.
                                                                                                                   --------
                                                                                                                
(3.3)        Restated By-Laws of the Company, as amended through February 2, 1997 (filed herewith).                   16

(10.42)      Non-Compete Agreement dated September 3, 1997, by the Registrant and Vernon L. Wells                     31
             (filed herewith).

(10.43)      Severance Agreement dated September 15, 1997, by the Registrant and Robert C. Verfurth (filed            34
             herewith).

(27.1)       Financial Data Schedule (filed herewith).                                                                41