To compare the antioxidative activities of fish skin and bovine skin gelatin hydrolysate, gelatin hydrolysates from Alaska pollack and bovine skin were prepared by various enzymatic hydrolysis methods (1st step, Alcalase; 2nd step, pronase E; 3rd step, collagenase) using a continuous three-step membrane reactor. The molecular weight distributions of the 1st, 2nd and 3rd step hydrolysates were 7∼10 kDa, 2∼5 kDa and 0.7∼0.9 kDa, respectively. The antioxidative activity of fish skin gelatin hydrolysate was stronger than that of bovine skin gelatin hydrolysate, and in particular, both of 2nd step hydrolysates showed more antioxidative activity than hydrolysates of any other step. The optimum antioxidative activity concentration of the 2nd step hydeolysates of fish and boving skin were 1% (w/w) in a linoleic acid water-alcohol emulsion. In cultured cells exposed to t-butyl hydroperoxide (t-BHP), the 2nd step hydrolysate of fish skin gelatin delayed cell death most. These results suggest that the antioxidative activity of fish skin gelatin hydrolysate is higher than that of bovine skin gelatin hydrolysate because of their different amino acid contents.