Fourier transform infrared (FTIR) technique has been used to characterize chemical changes induced by gamma irradiation of acrylamide (AA)-2-acrylamide-2-methyl propane sulfonic acid (AMPS) (AAAMPS) copolymer. FTIR spectra observed for unirradiated AAAMPS copolymer has shown characteristic absorption bands at 3450, 2930, 1720, 1620, 1450, 1370, 1250, 1080 cm-1 positions, which characterize both AA and AMPS monomers. While on irradiation some of the absorption bands are found prone to gamma irradiation. Among them 3450, 1720, 1620 and 1050 cm-1 absorption bands are more prominent. As these bands represent sulfonic acid, ester carbonyl and amide carbonyl groups cleavage of these groups is anticipated on irradiation of the copolymer.