EXHIBIT 5




                          WILLKIE FARR & GALLAGHER LLP
                               787 Seventh Avenue
                          New York, New York 10019-6099




August 16, 2005

W. R. Berkley Corporation
475 Steamboat Road
Greenwich, Connecticut 06830

Ladies and Gentlemen:

We have acted as counsel to W. R. Berkley Corporation (the "Company"), a
corporation organized under the laws of the State of Delaware, with respect to
the Company's Registration Statement on Form S-8 (the "Registration Statement")
to be filed by the Company with the Securities and Exchange Commission on or
about August 16, 2005, in connection with the registration under the Securities
Act of 1933, as amended (the "Act"), by the Company of an aggregate of $500,000
of Deferred Compensation Obligations (the "Obligations") and an indeterminable
number of shares of the Company's common stock, par value $0.20 per share (the
"Shares"), issuable under the W. R. Berkley Corporation Deferred Compensation
Plan for Directors (the "Plan").

We have examined, among other things, originals and/or copies (certified or
otherwise identified to our satisfaction) of such documents, papers, statutes
and authorities as we have deemed necessary to form a basis for the opinion
hereinafter expressed. In our examination, we have assumed the genuineness of
all signatures and the conformity to original documents of all copies submitted
to us. As to various questions of fact material to our opinion, we have relied
on statements and certificates of officers and representatives of the Company.

Based on the foregoing, we are of the opinion that (i) the Obligations have been
duly authorized for issuance and, when issued in accordance with the terms of
the Plan, will be legal, valid and binding obligations of the Company, except
that the enforceability of the Obligations may be limited by bankruptcy,
insolvency, fraudulent conveyance, reorganization, moratorium or other similar
laws relating to or affecting creditors' rights generally, regardless of whether
that enforceability is considered in a proceeding in equity or at law and (ii)
the Shares to be newly issued by the Company under the Plan, when duly issued,
sold and paid for in accordance with the terms of the Plan, will be legally
issued, fully paid and non-assessable.

This opinion is limited to the General Corporation Law of the State of Delaware
and the federal laws of the United States of America.

We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement. In giving such consent, we do not thereby admit that we
are in the category of persons whose consent is required under Section 7 of the
Act.

Very truly yours,

/s/ Willkie Farr & Gallagher LLP