This study aimed to determine the anti-mutagenic property of fish oil from Tamban (Sardinella lemuru Family Clupeidae) in Mitomycin C – induced female ICR mice. Initially, twelve mice were selected for acute oral toxicity testing. The resulted LD50 dose was 2000 mg/kg b.w. Twenty-five mice were then randomly divided into five groups: group I – positive control; group II- negative control and groups III, IV and V as experimental groups. Group I was given 5 mg/kg b.w. of Mitomycin C, group II 5 mL/ kg b.w. of normal saline solution, lastly groups III, IV and V received ¼ LD50 (500 mg/kg b.w), ½ LD50 (1000 mg/ kg b.w.), ¾ LD50 (1500 mg/ kg b.w.) of fish oil for seven days, respectively. After the last dose, Mitomycin C was administered intra peritoneal. After 24 hours, bone marrows were obtained and Micronucleus Test was performed. About two thousand erythrocytes were counted for the presence of Micronucleated Polychromatic Erythrocytes (MNPCE) and Polychromatic Erythrocytes (PCE). The results showed that 500 mg per kilogram body weight of Tamban fish oil could exhibit anti-mutagenic property comparable to the negative control. It also possessed the greatest MNPCE inhibition. However, 1000 mg per kilogram body weight and 1500 mg kilogram body weight showed no significant difference with the positive control and significant difference with the negative control. The results proved that the fish oil extract possessed potential anti-mutagenic property against Mitomycin C-induced female ICR mice.