EXHIBIT 10.20



                               AMENDING AGREEMENT

         THIS AGREEMENT made as of the 1st day of December, 1998.

BETWEEN:

                      SUN LIFE ASSURANCE COMPANY OF CANADA
                       (hereinafter called the "Landlord")

                                                               OF THE FIRST PART

AND:

                         MDSI MOBILE DATA SOLUTIONS INC.
                        (hereinafter called the "Tenant")

                                                              OF THE SECOND PART


     WHEREAS by a lease (the "Lease") dated the 18th day of September, 1997, the
Landlord demised to the Tenant part of the property  municipally  known as 10271
Shellbridge Way, Richmond, British Columbia, such premises are more particularly
described in the Lease, for the term and on the terms and conditions therein set
out;

     AND WHEREAS  effective  December 1, 1998, the parties hereto have agreed to
amend the Lease;

     NOW  THEREFORE  THIS  INDENTURE  WITNESSETH  that in  consideration  of the
premises,  the sum of ONE  DOLLAR  ($1.00)  of lawful  money of Canada and other
valuable  consideration  paid  by each  party  to the  other  (the  receipt  and
sufficiency  whereof is hereby  acknowledged),  the parties hereto  covenant and
agree as follows:

1.   The  parties  hereto  acknowledge,  confirm  and  agree  that  Clause  1.01
     "Premises"  of the Lease shall be amended to read 96,816  square feet,  and
     Schedule  "A" of the Lease shall be replaced  with  Schedule  "A"  attached
     hereto.

2.   The parties hereto acknowledge,  confirm and agree that Schedule C, Section
     D.1 being  referred to in Clause  1.04  "Basic  Rent" of the Lease shall be
     deleted in its entirety and replaced with the following to read:

     During  the  term  of the  lease,  Basic  Rent  shall  be due  and  payable
     commencing December 1, 1998 as follows:

     For the period December 1, 1998 to and including  November 30, 2003,  Basic
     Rent due and  payable to the  Landlord  shall be ONE MILLION  FOUR  HUNDRED
     FIFTY-TWO  THOUSAND TWO HUNDRED  FORTY  DOLLARS  ($1,452,240.00)  per annum
     payable in equal monthly  instalments  of ONE HUNDRED  TWENTY-ONE  THOUSAND
     TWENTY DOLLARS ($121,020.00).

     For the period December 1, 2003 to and including  November 30, 2008,  Basic
     Rent due and  payable to the  Landlord  shall be ONE MILLION  FIVE  HUNDRED
     NINETY-SEVEN  THOUSAND FOUR HUNDRED SIXTY-FOUR DOLLARS  ($1,597,464.00) per
     annum  payable in equal  monthly  instalments  of ONE HUNDRED  THIRTY-THREE
     THOUSAND ONE HUNDRED TWENTY-TWO DOLLARS ($133,122.00).

3.   The  parties  hereto  acknowledge,  confirm  and  agree  that in all  other
     respects  the terms and  conditions  of the Lease  remain in full force and
     effect,  unchanged and unmodified,  except as amended by this agreement, in
     accordance with the terms and conditions of the Lease, as amended hereby.


<PAGE>

4.   Except as  specifically  stated in this  agreement,  any expression used in
     this agreement has the same meaning as the corresponding expression used in
     the Lease.

5.   This  agreement  shall  enure to the  benefit  of and be  binding  upon the
     parties  hereto and their  respective  successors and assigns in accordance
     with the Lease.

     IN WITNESS WHEREOF the parties have hereunto  executed this agreement under
seal as of the day and year first above written.

SUN LIFE ASSURANCE COMPANY OF CANADA        )
                                            )
                                            )
                                            )
Per:    /s/ F.W. Crockett                   )                c/s
     ---------------------------------------)
              F.W. Crockett                 )
             Director, Leasing              )
                                            )
                                            )
Per:    /s/ S.J. Larsen                     )
     ---------------------------------------)
               S.J. Larsen                  )
       Director, Property Management        )




MDSI MOBILE DATA SOLUTIONS INC.             )
                                            )
                                            )
                                            )
Per:       /s/ Kenneth R. Miller            )                c/s
     ---------------------------------------)
                                            )
                                            )
                                            )
                                            )
Per:       /s/ Robert Cruickshank           )
     ---------------------------------------)











                                       2
<PAGE>




                                  SCHEDULE "A"




     Explanatory Plan of Leased Areas Comprising the Ground Floor, Second Floor,
Third Floor and Roof Floor of a 3-Storey  Building  Situated on Lot 115,  Except
Part  Subdivided  by Plan 63226,  Section 26, Block 5 North,  Range 5 West,  New
Westminster District, Plan 45786



                            [Diagram of leased area]



                                                                        INITIALS

                                                           [Initials] [Initials]