Exhibit 99.1

W. R. BERKLEY CORPORATION                   NEWS
475 STEAMBOAT ROAD                          RELEASE
GREENWICH, CONNECTICUT 06830
(203) 629-3000

FOR IMMEDIATE RELEASE

                                            CONTACT: Eugene G. Ballard
                                                     Chief Financial Officer
                                                     (203) 629-3000

                  W. R. BERKLEY CORPORATION ESTIMATES POTENTIAL
                  LOSSES RELATED TO HURRICANES FRANCES AND IVAN

      GREENWICH, CT, SEPTEMBER 21, 2004 -- W. R. BERKLEY CORPORATION (NYSE: BER)
today reported its initial estimate of losses attributable to Hurricanes Frances
and Ivan. Although potential claims information is preliminary, the Company does
not expect the combined net after-tax losses from both storms to exceed $10
million in the aggregate. These claims are a result of the Company's commercial
lines insurance and reinsurance operations, as well as its participation in
Lloyds'.

      Founded in 1967, W. R. Berkley Corporation is an insurance holding company
that operates in five segments of the property casualty insurance business:
specialty insurance, regional property casualty insurance, alternative markets,
reinsurance and international.

      This is a "Safe Harbor" Statement under the Private Securities Litigation
Reform Act of 1995. Any forward-looking statements contained herein, including
statements related to our outlook for the industry and for our performance for
the year 2004 and beyond, are based upon the Company's historical performance
and on current plans, estimates and expectations. The inclusion of this
forward-looking information should not be regarded as a representation by us or
any other person that the future plans, estimates or expectations contemplated
by us will be achieved. In particular, statements and estimates with respect to
Hurricane Charley are preliminary in nature and subject to future revision. Any
forward-looking statements are subject to various risks and uncertainties,
including but not limited to, the cyclical nature of the property casualty
industry, the long-tail and potentially volatile nature of the reinsurance
business, product demand and pricing, claims development and the process of
estimating reserves, the uncertain nature of damage theories and loss amounts,
increases in the level of our retention, natural and man-made catastrophic
losses, including as a result of terrorist activities, the impact of
competition, the availability of reinsurance, the ability of our reinsurers to
pay reinsurance recoverables owed to us, investment risks, including those
relating to fixed income securities, merger arbitrage investments, and other
equity securities, exchange rate and political risks relating to our
international operations, legislative and regulatory developments, changes in
the ratings assigned to us by ratings agencies, the availability of dividends
from our insurance company subsidiaries, our ability to successfully acquire and
integrate companies and invest in new insurance ventures, our ability to attract
and retain qualified employees, and other risks detailed from time to time in
the Company's filings with the Securities and Exchange Commission. These risks
could cause actual results of the industry or our actual results for the year
2004 and beyond to differ materially from those expressed in any forward-looking
statement made by or on behalf of the Company. Any projections of growth in the
Company's net premiums written and management fees would not necessarily result
in commensurate levels of underwriting and operating profits. Forward-looking
statements speak only as of the date on which they are made, and the Company
undertakes no obligation to update publicly or revise any forward-looking
statement, whether as a result of new information, future developments or
otherwise.

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