EXHIBIT 10.1

July 6, 2000


Dr. Nassim Usman
RPI
2950 Wilderness Place
Boulder, CO 80301

Dear Nassim:

     This letter is intended to confirm the modified terms of employment offered
to you by Ribozyme Pharmaceuticals, Inc. ("RPI"), and acknowledge your
acceptance of employment on the terms detailed below.

Position:                 Vice President of Research and Development and
                          Corporate Officer

Effective date:           August 1, 2000

Base Salary:              $230,000/year

Cash Bonus:               Up to 20% of base salary; based on achievement of
                          mutually agreed goals

Reporting to:             CEO and President

Equity Participation:     Additional grant of options on 20,000 shares of RPI
                          common stock from the shares reserved under a stock
                          option pool; exercise price at market closing price on
                          August 1, 2000; (half will vest over 5 years; half
                          vest on achievement of mutually agreed performance
                          goals)

Offer Expiration:         This offer will expire on July 15, 2000, if not
                          accepted.

     All other terms and benefits will continue per RPI's existing benefits
programs.

     Congratulations on your significant accomplishments and promotion, and we
are very excited about the prospect of many important contributions to RPI in
the years to come.

                                                Sincerely,

                                                /s/ Dr. Ralph E. Christoffersen

                                                Ralph E. Christoffersen, PhD
                                                CEO and President
REC/a

Agreed and accepted:
Date: July 6, 2000

Signature: /s/ Dr. Nassim Usman
Name: Nassim Usman, Ph.D.

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