CERTIFICATION PURSUANT TO RULE 30A-2(B) UNDER THE 1940 ACT AND
                     SECTION 906 OF THE SARBANES-OXLEY ACT

I,  Bruce  N.  Alpert,  Principal  Executive  Officer  of  GAMCO  Global  Series
Funds, Inc. (the "Registrant"), certify that:

         1.       The Form N-CSR of the Registrant (the "Report") fully complies
                  with  the  requirements  of  Section  13(a)  or  15(d)  of the
                  Securities Exchange Act of 1934, as amended; and

         2.       The information  contained in the Report fairly  presents,  in
                  all material respects,  the financial condition and results of
                  operations of the Registrant.


Date:    03/01/2007            /s/ Bruce N. Alpert
     -------------------       -------------------------------------------------
                               Bruce N. Alpert, Principal Executive Officer


I, Agnes Mullady, Principal Financial Officer & Treasurer of GAMCO Global Series
Funds, Inc. (the "Registrant"), certify that:

         1.       The Form N-CSR of the Registrant (the "Report") fully complies
                  with  the  requirements  of  Section  13(a)  or  15(d)  of the
                  Securities Exchange Act of 1934, as amended; and

         2.       The information  contained in the Report fairly  presents,  in
                  all material respects,  the financial condition and results of
                  operations of the Registrant.


Date:    03/01/2007             /s/ Agnes Mullady
     -------------------        ------------------------------------------------
                                Agnes Mullady,
                                Principal Financial Officer & Treasurer