Columbia Bancorp Recognizes $2.1 Million Loan Charge-Off; Resolving a
                       Relationship With a Single Borrower

    THE DALLES, Ore., May 7 /PRNewswire-FirstCall/ -- Columbia Bancorp (Nasdaq:
CBBO), the financial holding company for Columbia River Bank, announced today it
plans to recognize a charge-off of $2.1 million on a single loan to a potato
producer operating out of the Columbia Basin. Columbia River Bank plans to
increase the loan loss provision by $1.7 million in order to cover the
write-down in excess of the specific reserve for this single loan. The loan was
classified as a non-performing asset in the third quarter of 2006 and remained
in this classification at March 31, 2007. The remaining loan balance after the
charge off will be $278,000. Management expects the liquidation of collateral
consisting of farm equipment to cover the remaining balance.

    At the close of the first quarter of this year, estimates of collateral
value indicated that the stored potato crop and equipment would be sufficient to
cover the $2.38 million loan balance. Inspections of the potatoes stored for
processing indicated they were suitable for sale and delivery to market.
Subsequently, the bank assumed contracts to sell the potatoes to processing
facilities. Recent deliveries under one of these contracts were rejected due to
deterioration in the quality of the collateral. This led to the decision to
write-down the entire amount of this loan except for that portion covered by
equipment values.

    "Our internal credit ratings reflect an overall improvement in quality,
which we believe is now at its best level since 2001," stated Britt Thomas,
Executive Vice President and Chief Credit Officer. "This reflects improving
borrower strength and repayment ability." On a pro-forma basis, non- performing
asset levels at March 31, 2007, net of this single potato producer, would be
reflected as $1.1 million or 0.1% of total assets.

    "We recognize the importance of building strength within our loan portfolio
and the value of our team members to understand and appreciate our customers as
business partners. The challenge faced with this borrower is an isolated event,"
stated Roger Christensen, President and Chief Executive Officer. "Columbia River
Bank's number one priority is to continue to pursue our goal of meeting the
needs of our customers, shareholders and employees."

    ABOUT COLUMBIA BANCORP

    Columbia Bancorp (www.columbiabancorp.com) is the financial holding company
for Columbia River Bank, which operates 21 full-service branches located in The
Dalles (2), Hood River, Bend (3), Madras, Redmond (2), Pendleton, Hermiston,
McMinnville, Lake Oswego, Canby and Newberg, Oregon, and in Goldendale, White
Salmon, Sunnyside, Yakima, Pasco and Richland, Washington. In addition, Columbia
River Bank has three limited service branches located in retirement homes, one
in Bend, Oregon and two in McMinnville, Oregon. To supplement its community
banking services, Columbia River Bank also provides mortgage-lending services
through Columbia River Bank Mortgage Team and brokerage services through CRB
Financial Services Team.

    FORWARD LOOKING STATEMENTS

    This press release contains forward-looking statements about plans and
anticipated results of operations and financial condition relating to Columbia
Bancorp. These statements include statements about management's present plans
and intentions about our strategy, growth, and deployment of resources, and
about management's expectations for future financial performance, including
anticipated performance of our loan portfolio. Readers can sometimes identify
forward-looking statements by the use of prospective language and context,
including words like "may", "will", "should", "expect", "anticipate",
"estimate", "continue", "plans", "intends", or other similar terminology.
Because forward-looking statements are in art, an attempt to project future
events and explain management's current plans, they are subject to various risks
and uncertainties that could cause our actions and our financial and operational
results to differ materially from those set forth in such statements. These
risks and uncertainties include our ability to estimate accurately the potential
for losses inherent in our loan portfolio, economic and other factors that
affect the collectibility of our loans, and the impact of competition and
fluctuations in market interest rates on Columbia's revenues and margins. Our
filings with the Securities and Exchange Commission ("SEC") from time to time
discuss other risks and uncertainties that may impact our financial condition
and results of operations. Information presented in this release is accurate as
of the date first appearing above, and we cannot undertake to update our forward
looking statements or the factors that may cause us to deviate from them.

SOURCE  Columbia Bancorp
    -0-                             05/07/2007
    /CONTACT:  Roger L. Christensen, President and CEO, +1-541-298-6633,
rchristensen@columbiabancorp.com, or Greg B. Spear, Executive Vice President,
CAO, CFO, +1-541-298-6612, gspear@columbiabancorp.com, both of Columbia
Bancorp/
    /Web site:  http://www.columbiabancorp.com/
    (CBBO)