EXHIBIT 10.4

                                AGREEMENT

IT IS AGREED this ____ day of August 2001, by and between Jere Northrop ("JN")
and Bion Environmental Technologies, Inc. ("BION") as follows:

WHEREAS BION is entering into agreements concerning simplification of BION's
capital structure:

AND WHEREAS JN considers such simplification to be in the best interests of
BION and JN;

NOW THEREFORE, IN CONSIDERATION of the mutual promises and covenants herein:

1)   JN agrees to and does hereby amend the promissory note attached hereto
     as Exhibit A ("Note") to provide that:

     a)   The term of the Note shall be extended to April 30, 2002;
     b)   The Note (principal and interest) shall be completely converted to
          shares of common stock of BION (with an effective registration
          statement related to resale of such shares) upon the earlier of
          April 29, 2002 or the conversion of BION's outstanding Convertible
          Bridge Notes and 2001 Convertible Notes (collectively "CV Notes")
          at the lower of: 1) $2.25 per share, or ii) the conversion price of
          the CV Notes;
2)   JN and BION cancel 103,000 options exercisable at $2.25 per share
     until 12/31/01;
3)   BION and JN agree that, subject to agreement of necessary third parties,
     effective September 1, 2001, Jon Northrop shall be released from the
     restrictions on sale of BION securities owned by Jon Northrop set forth
     in a Shareholder's Agreement (dated  December 23, 1999), as amended;
4)   JN and BION agree to execute such other documents as may be necessary to
     properly carry out the transactions set forth herein.
5)   The Agreement is subject to ratification by BION's Board of Directors on
     or before September 15, 2001.

BION Environmental Technologies, Inc.          Jere Northrop


By:                                            By: /s/ Jere Northrop
    ---------------------------------             --------------------------
         Authorized Officer                         Jere Northrop


                                                                   EXHIBIT A
Initial Principal:  $230,000

Date Due:  December 31, 2001


                           PROMISSORY NOTE ("Note")

     FOR VALUE RECEIVED, the undersigned, Bion Environmental Technologies,
Inc., a Colorado corporation ("MAKER"), hereby promises to pay to the order of
Jere Northrop ("HOLDER"), and his successors and assignees, at 1961 Tonawanda
Creek Rd., Amherst, New York 14228, or at such other place as the HOLDER of
this Note may from time to time designate in writing, all sums due under this
Note (plus interest) in lawful and immediately available money of the United
States.  The initial principal of this loan is $230,000.  Interest shall be
accrued and added to principal at one percent (1.0%) per month from date owed
by MAKER.  All outstanding principal and interest shall be due and payable on
or before December 31, 2001, if not previously paid.  If this Note or interest
due hereunder is not paid when due or declared due hereunder, the principal
shall draw interest at the rate of one and one half percent (1.5%) per month.

     Upon default by the MAKER of the timely payment of principal or interest
due hereunder or upon any Event of Default as hereinafter defined, the HOLDER
may, in its sole discretion, withhold any payments due and payable to MAKER
and apply same to the MAKER's obligations hereunder.  In addition, upon any
Event of Default, the HOLDER may declare the full amount of this Note due and
payable.

     If any one or more of the following events ("Events of Default") shall
occur for any reason whatsoever (and whether such occurrence shall be
voluntary or involuntary or come about or be effected by operation of law,
pursuant to or in compliance with any judgment, decree of order of any court,
or any order, rule or regulation of any administrative or governmental body,
or otherwise) the HOLDER of this Note may, at its option, upon written notice
to MAKER, declare this Note and any other promissory note issued by MAKER to
HOLDER (whether or not then due in accordance with its terms) to be due and
payable, whereupon the entire balance of this Note shall forthwith become and
be due and payable:

          (a)  MAKER fails to make payment of principal or of interest on this
Note or any other obligation of MAKER when such shall become due and payable,
whether at the stated maturity thereof or by acceleration or otherwise;

          (b)  MAKER (1) admits its inability to pay its debts as they become
due; (2) files a petition in bankruptcy or makes a petition to take advantage
of an insolvency act; (3) makes an assignment for the benefit of creditors;
(4) commences a proceeding for the appointment of a receiver, trustee,
liquidator, or conservator of itself or of the whole or any substantial part
of its properties; (5) files a petition or answer seeking reorganization or
arrangement or similar relief under the federal bankruptcy laws or any other
applicable law or statute or the United States or any State;

          (c)  MAKER (1) is adjudged as bankrupt, (2) a court enters an order,
judgment or decree, appointing a receiver, trustee, liquidator or conservator
of MAKER or of the whole or any substantial part of its properties, or approve
a petition filed against MAKER seeking reorganization or similar relief under
the federal bankruptcy laws or any other applicable law or statute of the
United States or any state; (3) under the provisions of any other law for the
relief or aid of debtors, a court assumes custody or control of MAKER or the
whole or any substantial part of its properties; (4) there is commenced
against MAKER any proceeding for any of the foregoing relief; (5) a petition
in bankruptcy is filed against MAKER; or (6) MAKER by any act indicates its
consent to approval of or acquiescence in any such proceeding or petition.

     Except as otherwise hereinabove expressly provided, MAKER hereby waives
diligence, demand, protest, presentment and all notices (whether of
nonpayment, dishonor, protest, acceleration or otherwise) and consents to
acceleration of the time of payment, surrender or substitution of security or
forbearance, or other indulgence, without notice.

     Jurisdiction and venue shall be in a court of general jurisdiction
located in Denver, Colorado.  In the event that litigation is necessary to
collect the principal (and interest) of the Note, HOLDER shall be entitled to
reasonable attorneys' fees and litigation costs associated therewith.

                         BION ENVIRONMENTAL TECHNOLOGIES, INC.


                         By: __________________________________
                              Authorized Officer

Date:  May 21, 1999