EXHIBIT 10.24

                            FOURTH ADDENDUM TO LEASE

This Fourth  Addendum To Lease is made and entered into the 29th day of October,
1996,   between  Conifer  Prince  Street   Associates   (Landlord)  and  Patient
Infosystems, Inc. formerly DSMI Corporation (Tenant).

WITNESSETH: that Tenant currently leases and occupies approximately 7,224 square
feet of office space at 46 Prince Street,  Rochester, New York 14607 pursuant to
a Lease Agreement and First, Second and Third Addendums To Lease, dated February
22, 1995, August 18, 1995, November 17, 1995 and March 28, 1996, respectively.

WHEREAS, Tenant and Landlord desire to expand Tenant's Lease Premises to include
approximately  5,893 square feet of office space located on the third and fourth
levels of the Building as  illustrated  by Exhibit A-4 attached  hereto and made
part of this  Fourth  Addendum  To Lease  and  certain  provisions  of the Lease
Agreement and First, Second and Third Addendums To Lease stated above.

NOW,  THEREFORE,  it is mutually  agreed  upon by Landlord  and Tenant to modify
certain provisions of the Lease as follows:

1. Effective  December 1, 1996,  Tenant's lease premises shall be  approximately
13,117 rentable square feet.

2. Effective  December 1, 1996, Tenant agrees to pay, Base Rent for space leased
on the lower level of the  Building,  consisting of  approximately  1,720 square
feet as follows:

                       Period                        $/Sq.ft.           Monthly
                  Month-to-Month                     Base Rent         Base Rent
                  12/1/96-2/28/97                    $12.00            $1,720.00
                  3/1/97-2/28/98                      $12.50           $1,791.67
                  3/1/98-2/28/99                      $13.00           $1,863.33
                  3/1/99-11/30/99                     $13.50           $1,935.00

3.  Landlord or Tenant may  terminate the  obligations  of the Lease  Agreement,
First,  Second and Third  Addendums To Lease stated  above.  related to Tenant's
lower  level space of the  Building,  as stated in  Paragraph  2 above,  without
penalty, by providing the other with a minimum of thirty (30) days prior written
notice of its desire to terminate said obligations.

4. Effective  December 1, 1996, Tenant agrees to pay, Base Rent for space leased
on  the  first,  third  and  fourth  levels  of  the  Building,   consisting  of
approximately 11,397 square feet as following:

                       Period                        $/Sq.ft.           Monthly
                  Month-to-Month                     Base Rent         Base Rent
                  12/1/96-2/28/97                    $13.00           $12,346.75
                  3/1/97-2/28/98                      $13.50          $12,821.63
                  3/1/98-2/28/99                      $14.00          $13,296.50
                  3/1/99-11/30/99                     $14.50          $13,771.38

5. Effective upon the full  execution of this Fourth  Addendum To Lease,  Tenant
hereby exercises it extension  option, as stated in Paragraph  1,"TERM",  of the
Lease  Agreement,  with the  exception  that the term of said  extension  option
period is modified, in part, to provide for a lease termination date of November
30, 1999.

6. Effective upon the full execution of this Fourth Addendum To Lease, Paragraph
8 of the First  Addendum To Lease will become null and void and the Lease,  with
the exception of the provisions stated as in Paragraph 3 of this Fourth Addendum
To Lease,  shall no longer provide  Tenant with a right to early  termination of
the Lease.

7. Landlord will patch and paint the walls, doors and trim within Tenant's space
located on the third and fourth levels of the Building. Tenant and Landlord must
agree upon paint color(s) prior to October 17, 1996. Additionally, Landlord will
install,  within the third level area of Tenant's  demised  premises  only,  new
carpet in the common hallways,  receptionist  desk area,  internal  stairway and
private  offices.  Landlord  shall also  replace  existing  VCT  flooring in the
receptionist/storage area. Provided Landlord has enough carpet, Tenant agrees to
allow Landlord to install carpet,  in the common hallways and internal  stairway
of Tenant's  third level space,  that  matches the existing  carpet in the suite
adjacent to Tenant's  third level  space.  Carpet to be installed in the private
offices and receptionist area, stated above,  shall be a "Patcraft  Einstein" 28
ounce grade carpet or equal. If determined by Landlord's contractor, there is an
insufficient amount of the matching carpet stated above,  "Patcraft Einstein" 28
ounce  carpet or equal will be used as a substitute  in the common  hallways and
internal  stairway  mentioned above.  Landlord and Tenant must agree upon carpet
selection by October 17, 1996.  Landlord shall have the carpet in the large open
section of Tenant's fourth level space professionally  stretched.  Landlord will
also  professionally  shampoo the carpet on the entire  fourth  level and in the
third level conference  room.  Provided the above dates are adhered to, Landlord
will completed said work prior to December 1, 1996.

8. Effective December 1, 1996, Tenant's parking allowance will be increased from
25 on-site spaces to 41.

9. Effective December 1, 1996, Schedule A-3 of the Second Addendum To Lease will
be replaced by Schedule A-4, attached and made a part of this Fourth Addendum To
Lease .

Except as modified above,  all other terms and conditions of the Lease Agreement
and First,  Second and Third Addendus To Lease,  dated February 22, 1995, August
18,  1995,  November  17, 1995 and March 28,  1996,  respectively,  shall remain
unchanged and in full force and effect.

Agreed to by:                                       Agreed to by:
PATIENT INFOSYSTEMS                            CONIFER PRINCE STREET ASSOCIATES
FORMERLY DMSI CORPORATION

By:  /s/ Donald A. Carlberg                    By:  /s/ Dick Crossed           


Date:  October 25, 1996                        Date:  October 29, 1996         
   


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                                  SCHEDULE A-4

                             COMMON AREA MAINTENANCE

                                 ADDITIONAL RENT

                                    UTILITIES


                     Total Square Footage of Building 30,375

                     Square Footage Covered by Lease 13,117

                          Tenant's Share Electric 43.2%

                                                                ADDITIONAL RENT

Heating and Air Conditioning

The heat pump units serving the leased premises shall be individually gauged and
the monthly charges shall be calculated as set forth on the attached and further
explained as follows:

1. The heat pump units serving the lease  premises  shall be identified by model
number.

2. The actual heat pump operating  hours will be recorded for each month (column
3) and  multiplied  by the energy use factor  (column 4)  applicable to the heat
pump model to establish the total energy units (column 5).

3. The  total  energy  units  for all  heat  pumps  is then  added to the  total
auxiliary  usage to establish  the grand total usage and energy cost (total KWH)
for the building.

4. The grand total usage and energy cost is multiplied by the utility  company's
rate per KWH to establish the total cost for kilowatt hours.

5. The total  KWH are  divided  by the total  heat  pump  usage and  charges  to
establish the heat pump hourly rate (column 6).

6. The monthly  tenant  charge is the heat pump hourly  rate  multiplied  by the
total energy units (column 5).

7. Tenant will also pay 43.2% of general usage/common area electric.

         ADDITIONAL RENT

         Real Estate and Insurance Escalation

In  addition  to the  rents  set  forth in the  Lease,  and  heretofore  in this
Schedule,  with 1995 as the base year, Tenant shall pay 43.2% of the increase in
real  estate  taxes and other  government  levies in lieu of taxes  (payable  in
October of the  following  year),  and 43.2% of the  increase  in  property  and
liability insurance premiums (payable in February of the following year).