Exhibit 5

                    [Letterhead of Armstrong Teasdale LLP]

                                 June 28, 2001

Board of Directors
D&K Healthcare Resources, Inc.
8000 Maryland Avenue
Suite 920
St. Louis, MO  63105

Gentlemen:

     In our capacity as counsel for D&K Healthcare Resources, Inc., a Delaware
corporation (the "Company"), we have examined the Registration Statement on Form
S-3 (the "Registration Statement") in the form as proposed to be filed by the
Company with the Securities and Exchange Commission under the provisions of the
Securities Act of 1933, as amended, on June 28, 2001 relating to up to 390,080
shares of Common Stock, par value $0.01 per share (the "Common Stock"), to be
offered by the Company and certain selling stockholders to the public pursuant
to such Registration Statement. In this connection, we have examined such
records, documents and proceedings as we deem relevant and necessary as a basis
for the opinion expressed herein.

     Upon the basis of the foregoing, we are of the opinion that the shares of
Common Stock referred to above, to the extent actually issued pursuant to the
Underwriting Agreement, will have been duly and validly authorized and issued
and will be fully paid and non-assessable shares of the Company.

     We hereby consent to the filing of this opinion with the Securities and
Exchange Commission as an exhibit to the Registration Statement.

                                  Very truly yours,

                                  ARMSTRONG TEASDALE LLP