The purpose of this study was to evaluate the effect of hot water extracts of a fish, seaweed, and mushroom mixture (FSM extract) on the antioxidant and anticancer activities for use as health and functional food resources. DPPH radical scavenging activity increased from 13.4 to 93.5% when the FSM extract concentration ranged from 0.5 to 25 mg/mL. The reducing power increased from 0.04 to 1.06 OD 700 nm when the FSM extract concentration increased from 0.25 to 10 mg/mL. Nitrite scavenging activity increased from 10.3 to 96.9% when the FSM extract concentration increased from 1 to 25 mg/mL. The activities of alcohol dehydrogenase and acetaldehyde dehydrogenase in the FSM extractfed group were 2.45 and 6.12 units/min, respectively. The activities of CAT, SOD, and GSH-Px in the FSM extractfed group were 19.7 units/mg protein, 11.5 units/mg protein, and 16.9 units/mg protein/min, respectively. Cell viabilities of SNU213, SNU324, and SNU354 were 7.5, 9.4, and 8.9%, respectively. Cell viabilities of SNU719, SNU1, and SNU5 ranged from 14.6 to 16.8%. However, for SNU216, SNU484, SNU601, SNU638, SNU668, SNU16, and SNU520, they were below10%. These results demonstrate that the FSM extract can be used in the functional food, pharmaceutical, and cosmetic industries.