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                                                                   EXHIBIT 10.15


                                 PROMISSORY NOTE

$625,000.00                                                          May 6, 2002
                                                             Littleton, Colorado


         For consideration received, AspenBio, Inc., a Colorado corporation
("Maker") promises to pay to the order of Roger D. Hurst ("'Holder") in
accordance with the provisions set forth below, the principal sum of SIX HUNDRED
AND TWENTY FIVE THOUSAND. DOLLARS ($625,000:00), together with interest thereon
at the rate of eight percent (8%) per annum.

         Maker shall make one payment of all principal and interest outstanding
under this note on May 5, 2004. All amounts due pursuant to this Note shall be
paid in cash or other immediately available funds to Holder in care of Maker at
8100 Southpark Way, Unit B-1, Littleton, Colorado 80120, or at such other
address as may have been fixed by reasonable notice to Maker. Maker may prepay
the principal amount outstanding in whole or in part at any time without penalty
or premium. Any partial prepayment shall not postpone the due date of any
subsequent installment unless the Holder shall otherwise agree in writing.

         The loan represented by this Note is solely for commercial and business
purposes, and is not made in connection with a consumer transaction. The loan
represented by this Note is not for personal, family, agricultural or household
purposes. The loan represented by this Note is not a consumer loan within the
meaning of the Uniform Consumer Credit Code ("UCCC") and accordingly the UCCC
shall not apply to this Note.

         This Note shall be in default if Maker fails to cure within twenty (20)
days of receipt of written notice from Holder of default, it's failure to make
payment of principal or interest due under this Note when the same becomes due
and payable. From and after the date of any such default, all principal and
interest then due hereunder shall thereafter accrue interest at the rate of
twelve percent (12%) per annum. If default shall occur and be continuing and
Holder proceeds to enforce or pursue any legal or equitable remedies, Maker
agrees to pay all expenses incurred by Holder (including reasonable attorneys'
fees) incident to the enforcement of this Note.

         This Note and the obligations hereunder may got be assigned or
transferred to any person or party by Holder without the prior written consent
of Maker, which may be withheld in the sole and absolute discretion of Maker.
Maker may assign or transfer its rights and obligations to any person or party
at any time; provided, that any successor party shall have all rights and
obligations of Maker thereunder. The parties hereto, including Maker and any
guarantors, endorsers, successors and assigns hereby waive demand, presentment,
protest and notice of protest, diligence, and all other demands and notices in
connection with the delivery, acceptance, performance and enforcement of this
Note, and Maker agrees that Holder may extend the terms for payment or accept
partial payment without discharging or releasing Maker from any of its
obligations hereunder. This Note and its validity, construction, and performance
shall be governed in all respects by the laws of the state of Colorado.



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         IN WITNESS WHEREOF, Maker has caused this Note to be duly executed and
dated the day and year first above written.

                                       ASPENBIO, INC.
                                       A Colorado corporation


                                       By:
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                                       Name:  Gregory Pusey
                                       Title: Secretary