The present study was carried out to investigate the antioxidant effects of onion and ginger on the lipid peroxidation of mackerel during frozen storage. mackerels were reated with onion juice ginger juice tocopherol and BHA and stored at -18$^{circ}C$ for 6 weeks. lipid peroxidation in samples was estimated by the periodical measurements of acid value iodine value peroxide value carbonyl value 2-thiobarbituric acid value and fatty acid composition. The treatments with ginger and onion were effective on the suppression of acid value and carbonyl value of makerel oil during 4 to 6 weeks of frozen storage. The iodine value was not affected by the treatments with various antioxidants, The production of peroxides was delayed by ginger or onion treatment, the TBA value of the sample muscles was not lowered by the treatments, The treatment with onion resulted in less changes in the contents of $omega$-3 polyunsaturated fatty acids and in the P/S ration of fish oil than the control did. Results indicate that the applica-tion of ginger or onion juice on the surface of fishes may be useful to lower the degree of rancidity of fish during the froxaen storage.