March 15, 2000

U.S. Wireless Data, Inc.
2200 Powell Street, Suite 800
Emeryville, CA 94608

Gentlemen:

In connection with the private placement of securities (the "Private Placement")
of U.S.  Wireless Data, Inc. (the "Company")  through  Commonwealth  Associates,
L.P. (the "Placement Agent"),  the undersigned hereby represents that during the
period  commencing on the date hereof and ending on the first anniversary of the
final closing of the Private  Placement  (the  "Initial  Lock-Up  Period"),  the
undersigned  will not sell,  transfer or otherwise  dispose of any securities of
the Company that are currently  held by the  undersigned or that are acquired by
the undersigned during the Initial Lock-Up Period;  provide,  however,  that the
undersigned  shall have the right to (i)  transfer  up to 159,000  shares of the
Company's  Common Stock to its  employees  without the consent of the  Placement
Agent,  and (ii) sell up to 980,000  shares  (the  "Saleable  Shares") of Common
Stock  commencing  upon the  earlier  of June 1, 2000 or 30 days after the final
closing of the  Offering,  provided  that the  undersigned  shall first give the
Placement  Agent written notice of its intent to sell any or all of the Saleable
Shares  and the  Placement  Agent  shall  have 30 days from the  receipt of such
written  notice to  arrange  for such  shares to be sold in one or more block or
private  transactions  that will result in a net price to the  undersigned of at
least $7 7/8 per share or such lower price as agreed to by the undersigned  (the
"Target Price").  In the event that the Placement Agent is unable to arrange for
the sale of the Saleable Shares at the Target Price within such 3 days, then the
undersigned  shall be free to sell such shares in the open  market or  otherwise
without the consent of the Placement Agent. In addition,  the undersigned agrees
that the Initial  Lock-Up Period may, at the discretion of the Placement  Agent,
be extended  for up to an  additional  six months from the closing of any public
offering which is consummated  prior to the end of the Initial  Lock-Up  Period,
provided  that the  Placement  Agent extends the lock-up of all investors in the
Offering for the same period.  In order to enforce  this  covenant,  the Company
will impose  stop-transfer  instructions  with respect to all  securities of the
Company that are currently  held by the  undersigned or that are acquired by the
undersigned  during the Lock-Up  Period,  except for 980,000 and 159,000  shares
mentioned above.

Notwithstanding  the foregoing,  if the undersigned is an individual,  he or she
may transfer any  securities of the Company either during his or her lifetime or
on death by will or intestacy to his or her immediate  family or to a custodian,
trustee (including a trustee of a voting trust), executor or other fiduciary for
the account of his or her immediate  family, a trust, the beneficiaries of which
are  exclusively  the  undersigned  and/or a  member  or  members  of his or her
immediate family, or a charitable reminder trust;  provided that such transferee
agrees to be bound by the provisions of this lock-up agreement. For the purposes
of this  paragraph,  "immediate  family" shall mean spouse,  lineal  descendant,
father,  mother,  brother or sister of the transferor,  or lineal  descendant of
brother or sister of the transferor.



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Upon the execution  hereof,  this lock-up  agreement shall supercede any and all
other agreements with respect to the matter referred to herein.


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Signature                             Signature of Commonwealth Associates, L.P.
                                      or the Company


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Print Name                            Print Name