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 The GAMCO Growth Fund (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:    03/05/08       /s/ Bruce N. Alpert
     -------------      --------------------------------------------------------
                        Bruce N. Alpert, Principal Executive Officer



I, Agnes Mullady,  Principal Financial Officer and Treasurer of The GAMCO Growth
Fund (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:    03/05/08       /s/ Agnes Mullady
     -------------      --------------------------------------------------------
                        Agnes Mullady, Principal Financial Officer and Treasurer