Exhibit 5.1

                  [KUMMER KAEMPFER BONNER & RENSHAW LETTERHEAD]


                               September 3, 2003


NUVELO, INC.
675 Almanor Avenue
Sunnyvale, California 94085

Ladies and Gentlemen:

         We have acted as special Nevada counsel for Nuvelo, Inc., a Nevada
corporation (the "Company"), in connection with the Registration Statement on
Form S-8 ("Registration Statement") to be filed by the Company with the
Securities and Exchange Commission covering the offer and sale of an additional
3,943,160 shares of the Company's common stock, $0.001 par value per share
("Common Stock"), to be issued pursuant to the Nuvelo, Inc. 2002 Equity
Incentive Plan and the stock option agreements between the Company and certain
of its officers, employees and directors identified in the Registration
Statement (the "Stock Option Agreements").

         In rendering this opinion, we have examined and relied on the
following documents: (i) the Company's Articles of Incorporation, as amended,
and Bylaws, as amended, (ii) the resolutions adopted by the Board of Directors
of the Company on August 6, 2002, March 14, 2002, August 21, 2001, May 30,
2001, and February 6, 2001, (iii) the Registration Statement, and (iv) such
other documents, legal opinions and precedents, corporate and other records of
the Company, and certificates of public officials and officers of the Company
that we have deemed necessary or appropriate to provide a basis for the opinion.

         Based upon and subject to the foregoing and pursuant to Nevada law, in
our opinion, the shares of Common Stock of the Company that are being offered
and sold by the Company pursuant to the Registration Statement, when sold in
the manner and for the consideration contemplated by the Registration
Statement, will be legally issued, fully paid and non-assessable.

         We consent to the filing of this opinion as an Exhibit to the
Registration Statement.

                                    Very truly yours,


                                    -s- Kummer Kaempfer Bonner & Renshaw
                                    KUMMER KAEMPFER BONNER & RENSHAW