Previous phytochemical studies of Vigna angularis (Ohwi) Ohwi & Ohashi (Leguminosae) have shown the presence of saponins and flavonoids. From the seed of V. angularis, genistein-7-O-β-D-glucopyranoside (genistin) was isolated. Lifespan-extending effect of genistin was elucidated using Caenorhabditis elegans model system. Genistin showed potent lifespan extension of worms under normal culture condition. This compound also exhibited the protective effects against thermal and oxidative stress conditions. In the case of heat stress, genistin-treated worms exhibited enhanced survival rate, compared to control worms. In addition, genistin-fed worms lived longer than control worms under oxidative stress induced by paraquat. To verify the possible mechanism of genistin-mediated increased lifespan and stress resistance of worms, we investigated whether genistin might alter superoxide dismutase (SOD), catalase activities and intracellular ROS levels. Our results showed that genistin was able to elevate SOD and catalase activities of worms and reduce intracellular ROS accumulation in a dose-dependent manner.