January 19, 2000

Board of Directors
THERMOGENESIS CORP.
3146 Gold Camp Drive
Rancho Cordova, California 95670

RE:    Common Stock of THERMOGENESIS CORP.

Dear Gentlemen:

I have acted as general counsel to THERMOGENESIS  CORP., a Delaware  corporation
(the "Company"),  in connection with the registration of 4,720,562 shares of the
Company's  common stock (the  "Shares")  under the  Securities  Act of 1933,  as
amended (the  "Securities  Act"), of which 444,562 of the Shares will be offered
to holders of the Company's  warrants,  and all of which will be sold by selling
stockholders of the Company as further  described in the Company's  registration
statement  on Form  S-3  filed  under  the  Securities  Act  (the  "Registration
Statement").

For the purpose of rendering  this  opinion,  I examined  originals or copies of
such  documents  as deemed to be  relevant.  In  conducting  my  examination,  I
assumed,  without  investigation,   the  genuineness  of  all  signatures,   the
correctness of all certificates,  the authenticity of all documents submitted to
me as originals, the conformity to original documents of all documents submitted
as certified or photostatic  copies,  and the  authenticity  of the originals of
such copies,  and the accuracy and completeness of all records made available to
me by the Company.  In addition,  in rendering this opinion,  I assumed that the
Shares will be offered in the manner and on the terms  identified or referred to
in the Registration Statement, including all amendments thereto.

My opinion is limited  solely to matters  set forth  herein.  I am  admitted  to
practice  in the State of  California  and I express no opinion as to the law of
any other jurisdiction other than the laws of the State of Delaware and the laws
of the United States.

Based upon and subject to the foregoing,  after giving due regard to such issues
of law as I deemed relevant,  and assuming that (i) the  Registration  Statement
becomes  and  remains  effective,  and  the  prospectus  which  is a part of the
Registration   Statement  (the   "Prospectus"),   and  the  Prospectus  delivery
requirements  with  respect  thereto,  fulfill  all of the  requirements  of the
Securities Act, throughout all periods relevant to the opinion,  (ii) all offers
and sales of the Shares will be made in compliance  with the securities  laws of
the states having jurisdiction  thereof, and (iii) the Company receives,  to the
extent  applicable,  the consideration set forth in the Prospectus,  I am of the
opinion that the Shares issued are, and the Shares to be issued will be, legally
issued, fully paid and nonassessable.

2


I hereby  consent  in  writing  to the use of my  opinion  as an  exhibit to the
Registration  Statement and any amendment thereto.  By giving such consent, I do
not thereby  admit that I come within the category of persons  where  consent is
required under Section 7 of the  Securities Act or the rules and  regulations of
the Securities and Exchange Commission.

Sincerely,

/s/ DAVID C. ADAMS
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    David C. Adams
    General Counsel