Technical Abstract: Ethanol-water (70:30, v/v) extracts from the bran of rice seeds from twenty one pigmented and one nonpigmented rice cultivars were evaluated for antioxidative activities using the following tests: inhibition of peroxidation of linoleic acid; inhibition of peroxidation of rabbit lipid erythrocyte membranes; reduction of potassium ferricyanide; and scavenging of superoxide anions and hydroxyl radicals. With some exceptions, extracts from the pigmented rice seeds containing anthocyanins had higher antioxidative activity than the nonpigmented variety. The following pigmented varieties had the highest antioxidative activities in all tests: JumLalocal-1, Parnkhari 203, DZ78, LK1-3-6-12-1-1, and Elwee. A significant correlation was also noted between reducing power, inhibition of erythrocyte ghost membrane peroxidation, and superoxide anion and hydroxyl radical scavenging. The results suggest that (a) ferricyanide reducing power might be a useful simple index for large-scale evaluation of antioxidative potencies of natural products present in rice and other plant foods; (b) pigmented rice varieties with high antioxidative activities provide a genetic resource to develop new health-promoting, value-added rice cultivars.