SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
                               ------------------


                                  SCHEDULE 13D



                    Under the Securities Exchange Act of 1934

                                 Amendment No. 1

                        Integrated Security Systems, Inc.
------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    45812J101
------------------------------------------------------------------------------
                                 (CUSIP Number)

                                Russell Cleveland
                         Renaissance Capital Group, Inc.
                  8080 N. Central Expressway, Suite 210, LB-59
                            Dallas, Texas 75206-1857
                                 (214) 891-8294
------------------------------------------------------------------------------
                 (Name, Address, and Telephone Number of Person
                Authorized to Receive Notices and Communications)

                                  May 24, 2001
------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of This Statement)

If the filing person has previously  filed a statement on Schedule 13G to report
the  acquisition  which is the subject of this  Schedule 13D, and is filing this
schedule because of Rule 13d-1(e),  13d-1(f),  or 13d-1(g),  check the following
box [ ].


                         (Continued on following pages)







CUSIP No. 45812J101                                     13D
--------------------------------------------------------------------------------
1         NAME OF REPORTING PERSON                  I.R.S. IDENTIFICATION NUMBER
          Renaissance Capital Growth & Income Fund III, Inc.          75-2533518
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP        (a)      [ ]
                                                                 (b)      [x]
--------------------------------------------------------------------------------
3.       SEC USE ONLY
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
         TO ITEM 2(d) OR 2(e)                       [  ]
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
                  Texas
--------------------------------------------------------------------------------
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:
--------------------------------------------------------------------------------
         7.       SOLE VOTING POWER
                        21,944,758
--------------------------------------------------------------------------------
         8.       SHARED VOTING POWER
                        None
         -----------------------------------------------------------------------
         9.       SOLE DISPOSITIVE POWER
                        21,944,758
         -----------------------------------------------------------------------
         10.      SHARED DISPOSITIVE POWER
                        None
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                  21,944,758
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES                                                             [  ]
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN  ROW (11)
                  67.9%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
                  IV






CUSIP No. 45812J101                                     13D
--------------------------------------------------------------------------------
1        NAME OF REPORTING PERSON                   I.R.S. IDENTIFICATION NUMBER
         Renaissance US Growth & Incom                            None - Foreign
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP      (a)      [ ]
                                                               (b)      [x]
--------------------------------------------------------------------------------
3.       SEC USE ONLY
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
         TO ITEM 2(d) OR 2(e) [  ]
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
                  England
--------------------------------------------------------------------------------
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:
--------------------------------------------------------------------------------
         7.       SOLE VOTING POWER
                           21,108,446
         -----------------------------------------------------------------------
         8.       SHARED VOTING POWER
                           None
         -----------------------------------------------------------------------
         9.       SOLE DISPOSITIVE POWER
                           21,108,446
         -----------------------------------------------------------------------
         10.      SHARED DISPOSITIVE POWER
                           None
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                  21,108,446
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES                                                     [  ]
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN  ROW (11)
                  67.0%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
                  IV






Item 1.           Security and Issuer.

         This  statement  relates  to the  Common  Stock  ("Common  Shares")  of
Integrated  Security  Systems,  Inc. (the  "Company").  The principal  executive
offices of the Company  are  located at 8200  Springwood  Drive,  Irving,  Texas
75063.

Item 2.           Identity and Background.

         (a) This Statement is filed by Renaissance Capital Growth & Income Fund
III, Inc.  ("Renaissance  III"),  and  Renaissance  US Growth & Income Trust PLC
("Renaissance  PLC"); Renaissance III and Renaissance  PLC collectively referred
to herein as "Reporting Persons").

                  Certain  information  concerning  the  directors and executive
officers of the Reporting  Persons is set forth on Attachment 1 attached  hereto
and incorporated herein by reference.

         (b) Renaissance III is a business  development  company regulated under
the Investment Company Act of 1940, as amended,  and organized under the laws of
the State of Texas, with its principal  business and principal office at 8080 N.
Central Expressway, Suite 210, LB-59, Dallas, Texas 75206-1857.

                  Renaissance  PLC is an investment  trust  organized  under the
laws of England and Wales.  Its address in the United States is c/o  Renaissance
Capital Group, Inc., Investment Manager, 8080 N. Central Expressway,  Suite 210,
LB-59, Dallas, Texas 75206-1857.

                  The business addresses of the directors and executive officers
of the  Reporting  Persons are set forth on  Attachment 1 to this  Statement and
incorporated herein by reference.

         (c)      Renaissance  III  and  Renaissance  PLC  are  engaged  in  the
business  of  investing  principally  in  emerging or  undervalued  U.S.  public
companies.

         (d) Neither any of the Reporting  Persons nor, to the best knowledge of
such  persons,  any person  named in  Attachment 1 to this  Statement,  has been
convicted in a criminal  proceeding  in the past five years  (excluding  traffic
violations or similar misdemeanors).

         (e) Neither any of the Reporting  Persons nor, to the best knowledge of
such persons, any person named in Attachment 1 to this Statement, was during the
last five years a party to a civil  proceeding  of a judicial or  administrative
body of  competent  jurisdiction  as a result  of which  such  person  was or is
subject to a judgment, decree, or final order enjoining future violations of, or
prohibiting or mandating activities subject to, federal or state securities laws
or finding any violation with respect to such laws.

         (f) All persons named on Attachment 1 to this Statement are citizens of
the United States, except as otherwise indicated on such Attachment.

                                     Page 4





Item 3.           Source and Amount of Funds or Other Consideration.

                  The  total  amount of funds  required  by  Renaissance  III to
acquire the securities reported in Item 5(a) was $4,479,589.  The source of such
funds was capital of Renaissance III.

                  The  total  amount of funds  required  by  Renaissance  PLC to
acquire the securities reported in Item 5(a) was $4,313,463.  The source of such
funds was capital of Renaissance PLC.

Item 4.           Purpose of Transaction.

                  The Reporting  Persons each acquired  beneficial  ownership of
the Common Stock  reported in Item 5(a) both in the ordinary  course of business
for investment purposes and upon exchange of indebtedness in connection with the
financial  restructuring  of the Company.  The President and CEO of  Renaissance
Capital  Group,  Inc.,  the  investment  advisor  to  Renaissance  III  and  the
investment manager of Renaissance PLC, Russell Cleveland,  has been appointed to
the board of directors of the Company.

                  The Reporting  Persons may  participate  in  discussions  with
management or third parties in which the Reporting  Person may suggest or take a
position with respect to potential  changes in the  operations,  management,  or
capital structure of such companies as a means of enhancing  shareholder  value.
Such  suggestions  or  positions  may relate to one or more of the  transactions
specified  in  clauses  (a)  through  (j) of Item 4 of the  Schedule  13D  form,
including,  without  limitation,  such  matters  as  disposing  of one  or  more
businesses,  selling the  Company,  merging  with  another  Company or acquiring
another company or business, changing operating or marketing strategies, changes
in management or marketing, or restructuring the Company's capitalization.

                  Each  Reporting  Person  continues  to  assess  the  Company's
business,  financial  condition,  results of operations and  prospects,  general
economic  conditions,  the  securities  markets  in  general  and  those for the
Company's  securities in particular,  other  developments  and other  investment
opportunities,   as  well  as  the  Reporting  Person's  investment  objectives.
Depending on such assessments,  one or both of the Reporting Persons may acquire
additional  securities or may determine to sell or otherwise  dispose of some or
all of its holding of securities.

                  Other  than  as  described  above,  neither  of the  Reporting
Persons has any present  plans or  proposals  which relate to or would result in
any transaction, change, or event specified in clauses (a) through (j) of Item 4
of the Schedule 13D.

Item 5.           Interest in Securities of the Issuer.

                  (a)      Renaissance III beneficially owns  21,944,758  Common
Shares, and Renaissance PLC  beneficially owns  21,108,446  Common  Shares.  The
Reporting  Persons  beneficially  own  43,053,204  Common  Shares.   Based  upon
information filed  with  the  Securities and  Exchange  Commission,  the  Common

                                     Page 5





Shares  beneficially  owned by Renaissance  III,  Renaissance  PLC, and together
represent   approximately  67.9%,  67.0%,  and  81.2%,   respectively,   of  the
outstanding  Common Stock of the Company.  Renaissance  III and  Renaissance PLC
disclaim that they are members of a group for purposes of Regulation 13D.

                  The Common Shares  beneficially  owned by Renaissance  III are
comprised  of 393,259  shares of Common  Stock;  814,299  shares of Common Stock
issuable upon the exercise of warrants;  187,500 shares of Common Stock issuable
upon the  conversion  of 7,500  shares of Series D  Preferred  Stock;  2,589,945
shares of Common Stock  issuable  upon  conversion  of 20,720 shares of Series F
Convertible  Preferred Stock ("Series F Preferred Stock"); and 17,959,755 shares
of  Common  Stock  issuable  upon  conversion  of  143,678  shares  of  Series G
Convertible Preferred Stock ("Series G Preferred Stock"). The board of directors
of Renaissance III exercises  voting and investment  control over the securities
of the Company owned by it.

                  Renaissance  PLC is  deemed  the  beneficial  owner of  Common
Shares  comprised of 393,258  shares of Common Stock;  808,617  shares of Common
Stock  issuable  upon the exercise of warrants;  187,500  shares of Common Stock
issuable  upon the  conversion  of 7,500  shares  of Series D  Preferred  Stock;
2,589,945  shares of Common Stock  issuable upon  conversion of 20,720 shares of
Series F Preferred  Stock;  and 17,129,126  shares of Common Stock issuable upon
conversion of 137,033 shares of Series G Preferred Stock. The board of directors
of Renaissance PLC exercises  voting and investment  control over the securities
of the Company owned by it.

                  (b)  Holders of Series D Preferred  Stock are  entitled to one
vote for each share of Common  Stock into which such share of Series D Preferred
Stock could then be converted.  Presently,  the holder of each share of Series D
Preferred stock is entitled to 25 votes. Holders of Series F Preferred Stock are
entitled to vote with the holders of Common Stock, the Series D Preferred Stock,
the  Series E  Preferred  Stock , and the Series G  Preferred  Stock as a single
class on all matters on which  stockholders are entitled to vote,  including the
election of directors,  except as otherwise required by law. Holders of Series F
Preferred  Stock  are also  entitled  to vote  with any  other  class of  equity
securities which may vote with the holders of the Common Stock as a single class
with respect to any matter.  Holders of Series F Preferred Stock are entitled to
a number of votes per share of Series F  Preferred  Stock equal to the number of
shares of Common  Stock into which the  shares of Series F  Preferred  Stock are
convertible on the record date of the determination of stockholders  entitled to
receive  notice of and to vote on such  matter.  In  addition,  the  consent  of
holders of 80% of the Series F Preferred Stock and the Series G Preferred Stock,
voting together as a single class, will be required to (a) authorize, create, or
increase the  authorized  amount of any class of senior  stock or parity  stock,
other than Preferred Stock of the same class or securities to evidence bank debt
or asset  securitization  or (b) authorize a merger,  consolidation,  or sale of
assets, other than in the ordinary course of business, of the Company, including
the capital stock of the Company's  subsidiaries.  The consent of holders of 80%
of the Series F Preferred  Stock,  voting as a single class, will be required to
approve any action to amend the Company's certificate of incorporation or bylaws
that would  materially and adversely affect the rights of the Series F Preferred
Stock.


                                     Page 6





                  Holders of Series G  Preferred  Stock will be entitled to vote
with the holders of Common  Stock,  the Series D Preferred  Stock,  the Series E
Preferred  Stock,  and the  Series F  Preferred  Stock as a single  class on all
matters on which  stockholders  are entitled to vote,  including the election of
directors,  except as otherwise  required by law.  holders of Series G Preferred
Stock are also entitled to vote with any other class of equity  securities which
may vote with the holders of the Common  Stock as a single class with respect to
any  matter.  Holders of Series G  Preferred  Stock are  entitled to a number of
votes per share of Series G  Preferred  Stock  equal to the  number of shares of
Common Stock into which the Shares of Series G Preferred  Stock are  convertible
on the record  date of the  determination  of  stockholders  entitled to receive
notice of and to vote on such matter. In addition, the consent of holders of 80%
of the  Series G  Preferred  Stock  and the  Series F  Preferred  Stock,  voting
together  as a single  class,  will be required  (a) to  authorize,  create,  or
increase the  authorized  amount of any class of senior  stock or parity  stock,
other than Preferred Stock of the same class or securities to evidence bank debt
or securitization or (b) authorize a merger,  consolidation,  or sale of assets,
other than in the ordinary  course of business,  of the Company,  including  the
capital  stock of the Company's  subsidiaries.  The consent of holders of 80% of
the Series G  Preferred  Stock,  voting as a single  class,  will be required to
approve any action to amend the Company's certificate of incorporation or bylaws
that would  materially and adversely affect the rights of the Series G Preferred
Stock.

                  In  addition  to their  right to vote with the  holders of the
Common Stock on the election of directors, the Reporting Persons, as the holders
of the Series G Preferred Stock and the holders of the Series F Preferred Stock,
voting  together  as a  single  class,  are  entitled  to elect  two  additional
directors to the Company's board of directors.

                  Each of the  Reporting  Persons  has or  will  have  upon  the
exercise of the warrants  issued to it by the Company the sole power to vote and
dispose of all of the  Common  Shares  that it  beneficially  owns.  None of the
Reporting  Persons  shares  voting or  disposition  power with any  person  with
respect to the Common Shares.

                  (c) No  transaction  in the Common  Shares was  effected  by a
Reporting Person during the past 60 days, except as follows: (1) the issuance on
May 17, 2001, in connection with a financial  restructuring  of the Company,  to
Renaissance  III of 20,720 shares of Series F Preferred Stock and 137,678 shares
of Series G Preferred Stock and the issuance to Renaissance PLC of 20,720 shares
of Series F Preferred Stock and 131,033 shares of Series G Preferred  Stock, all
of which  shares were  issued in  exchange  for  approximately  $7.5  million of
promissory  notes  and  convertible  debentures  owned  by  Renaissance  III and
Renaissance  PLC,  including  accrued  interest,  in connection with a financial
restructuring  of the Company;  and (2) the  issuance on May 24, 2001,  of 6,000
shares of Series G Preferred  Stock to Renaissance III and the issuance of 6,000
shares of Series G Preferred Stock to Renaissance  PLC, all of which shares were
issued for a total of $300,000 cash.


                                     Page 7





                  (d) No person other than the  Reporting  Persons has the right
to receive or the power to direct the receipt of dividends from, or the proceeds
from the sale of, the Common Shares beneficially owned by the Reporting Persons.

                  (e)      Not applicable.

Item 6.           Contracts, Arrangements, Understandings, or Relationships With
                  Respect to Securities of the Issuer.

                  Not Applicable.

Item 7.           Material to be Filed as Exhibits.

                           Exhibit 1        Joint Filing  Agreement  Pursuant to
                                            Rule 13d-1(k)


                                   SIGNATURES

                  After  reasonable  inquire and to the best of their individual
knowledge and belief,  the  signatories  below certify that the  information set
forth in this  statement is true,  complete,  and correct as of this ____ day of
June, 2001.

                  The  persons  whose  signatures  appear  below agree that this
statement on Schedule 13D is filed on behalf of each of them.

                             RENAISSANCE CAPITAL GROWTH & INCOME FUND III, INC.




                             By:     ______________________________
                             Name: Russell Cleveland
                             Title:  President and Chief Executive Officer


                             RENAISSANCE US GROWTH & INCOME TRUST PLC




                             By:     _______________________________
                             Name: Russell Cleveland
                             Title:  Director

                                     Page 8





                                  ATTACHMENT 1

                  The name,  business address,  and principal  occupation of the
directors and executive officers of Renaissance III are as follows:

DIRECTORS
                                                                       Principal
Name                     Business Address                       Occupation

Edward O. Boshell, Jr.   c/o Renaissance Capital Group, Inc.    Director
                         8080 North Central Expressway
                         Suite 210, LB-59
                         Dallas, TX 75206-1857
Russell Cleveland        c/o Renaissance Capital Group, Inc.    Director
                         8080 North Central Expressway
                         Suite 210, LB-59
                         Dallas, TX 75206-1857
Peter Collins            c/o Renaissance Capital Group, Inc.    Director
                         8080 North Central Expressway
                         Suite 210, LB-59
                         Dallas, TX 75206-1857
Ernest C. Hill           c/o Renaissance Capital Group, Inc.    Director
                         8080 North Central Expressway
                         Suite 210, LB-59
                         Dallas, TX 75206-1857
OFFICERS

Russell Cleveland        c/o Renaissance Capital Group, Inc.    President and
                         8080 North Central Expressway          Chief Executive
                         Suite 210, LB-59                       Officer
                         Dallas, TX 75206-1857
John A. Schmit           c/o Renaissance Capital Group, Inc.    Vice President
                         8080 North Central Expressway
                         Suite 210, LB-59
                         Dallas, TX 75206-1857
Robert C. Pearson        c/o Renaissance Capital Group, Inc.    Vice President
                         8080 North Central Expressway
                         Suite 210, LB-59
                         Dallas, TX 75206-1857
Barbara A. Butschek      c/o Renaissance Capital Group, Inc.    Secretary and
                         8080 North Central Expressway          Treasurer
                         Suite 210, LB-59
                         Dallas, TX 75206-1857

                                     Page 9





                  The name,  business address,  and principal  occupation of the
directors and executive officers of Renaissance PLC are as follows:

DIRECTORS
                                                                       Principal
Name                                        Business Address          Occupation

Michael B. Cannan                 c/o Sinclair Henderson Limited        Director
                                23 Cathedral Yard
                                  Exeter EX11HB
Russell Cleveland                 c/o Sinclair Henderson Limited        Director
                                23 Cathedral Yard
                                  Exeter EX11HB
Ernest J. Fenton                  c/o Sinclair Henderson Limited        Director
                                23 Cathedral Yard
                                  Exeter EX11HB
Lord Mark Fitzalan Howard OBE     c/o Sinclair Henderson Limited        Director
                                23 Cathedral Yard
                                  Exeter EX11HB
C. A. Rundell, Jr.                c/o Sinclair Henderson Limited        Director
                                23 Cathedral Yard
                                  Exeter EX11HB
William W. Vanderfelt             c/o Sinclair Henderson Limited        Director
                                23 Cathedral Yard
                                  Exeter EX11HB

OFFICERS

None



                                     Page 10




                                    EXHIBIT 1

                JOINT FILING AGREEMENT PURSUANT TO RULE 13d-1(k)

                  The  undersigned  acknowledge  and  agree  that the  foregoing
statement on Schedule 13D is filed on behalf of each of the undersigned and that
all of each of the undersigned  without the necessity of filing additional joint
filing  agreements.  The undersigned  acknowledge that each shall be responsible
for the timely filing of such amendments,  and for the completeness and accuracy
of the information concerning it contained therein, but shall not be responsible
for the  completeness  and accuracy of the  information  concerning  the others,
except to the extent it knows or has reason to believe that such  information is
inaccurate.  This  Joint  Filing  Agreement  may be  executed  in any  number of
counterparts  and all of such  counterparts  taken together shall constitute one
and the same instrument.

                              RENAISSANCE CAPITAL GROWTH & INCOME FUND III, INC.




                              By:     ______________________________
                             Name: Russell Cleveland
                              Title:  President and Chief Executive Officer


                              RENAISSANCE US GROWTH & INCOME TRUST PLC




                              By:     _______________________________
                             Name: Russell Cleveland
                                 Title: Director







                                     Page 11