EXHIBIT 10.15

                              [NITROMED LETTERHEAD]

                                                        Michael D. Loberg, Ph.D.
                                                        CHIEF EXECUTIVE OFFICER
                                                        mloberg@nitromed.com

                                 April 22, 1999

Mr. Joseph Grimm
174 Marlborough Street
Boston, Massachusetts 02116

Dear Joe:

The Management and Board of NitroMed have enjoyed meeting you and are
enthusiastic to have you join our senior management team. As such, we would like
to formally offer you the position of Senior Vice President, Business
Development and Chief Financial Officer, reporting to me as Chief Executive
Officer.

The terms of the offer are described below:

     Start Date:               April 19, 1999

     Base Salary:              $180,000 to be reviewed annually and adjusted by
                               the Board's Compensation Committee to reflect
                               performance.

     Performance Bonus:        Beginning in 1999 an annual bonus based upon
                               performance and the achievement of milestones
                               mutually agreed upon by you, me and the Board of
                               Directors in an amount up to 22% of base salary
                               in accordance with the NitroMed Incentive
                               Compensation Plan (copy attached).

     Stock:                    Options granted under the Company's Stock Option
                               Plan of 100,000 shares of the Company's Common
                               Stock. These options will vest in equal
                               installments over a four year period, beginning
                               on the first anniversary of your employment in
                               accordance with the NitroMed Stock Option Plan
                               (copy attached). The exercise price of these
                               options will be the fair market value as set by
                               the Board of Directors on the day the Board
                               approves your option grant. The most recent price
                               is $0.72 per share.

                               Restricted Stock in the amount of 25,000 shares
                               of the Company's Common Stock. These shares will
                               be sold to you at the fair market value as set by
                               the Board of Directors, currently $0.72 per
                               share. The restriction will be lifted when the
                               NitroMed shares become publicly traded or upon a
                               "change of control". Your departure from the
                               Company prior to either of these events will
                               cause the Restricted Stock to be repurchased by
                               the Company at the then current fair



                               market value. A "change of control" means a sale
                               of all or substantially all of the assets of the
                               Company, or a merger or consolidation of NitroMed
                               which results in the voting securities of
                               NitroMed outstanding immediately prior thereto
                               ceasing to represent at least 50% of the combined
                               voting power of the surviving entity.

     Severance:                Should your employment with the Company be
                               terminated by the Company for reasons other than
                               cause, you will receive six months base salary as
                               termination payment and your options vested as of
                               the termination date will be exercisable for a 90
                               day period. If the termination by the Company is
                               within one year subsequent to a change of
                               control, then the termination payment will be
                               extended to one year's salary and the vesting of
                               all options will accelerate. Termination will
                               include actual termination by the Company as well
                               as constructive dismissal (defined to include a
                               reduction in responsibility, a reduction in
                               compensation benefits or a relocation outside a
                               50-mile radius from NitroMed's facility at the
                               time of termination).

     Agreements:               As a condition of employment, you will be
                               required to sign the Company's invention,
                               non-disclosure, and non-compete agreements.

We trust that these terms are satisfactory and look forward to having you work
with us to reach our corporate goals, and in the process provide a high return
to our shareholders and employees. Much work has been done to bring NitroMed to
the point where its platform technology is now being tested in the clinic. Much
is still to be done if efforts in R&D and Clinical Development are to truly
flower. The NitroMed team welcomes with enthusiasm and optimism your
participation in this exciting effort. Together we will manage the assets,
negotiate the ventures and build value.

If the above employment offer is acceptable please sign below and return one
copy to me for our files.

                                    Sincerely,


                                    /s/ Michael D. Loberg
                                    ---------------------
                                    Michael D. Loberg

Agreed and Accepted:


/s/ Joseph Grimm
--------------------
Joseph Grimm