Objectives : The purpose of this study was to estimate the antioxidant activity of water extract of Nelumbinis stamen (WNS) in GC-2 spd (ts) cells. Methods : we investigated the effect of WNS in mouse GC-2 spd (ts) cells by MTT assay. The protective effects of WNS against hydrogen peroxide-induced oxidative stress in GC-2 spd (ts) cells were examined by measuring cell viability. Lipid peroxidation levels and catalase were measured. Results : WNS showed cell viability as 101.9, 108.9, 111.8, 125.8, 134.5% in 2.5, 5, 10, 25, 50 ${mu}g/ml$ concentrations, respectively. The protective effect of WNS concentration was 2.5 ${mu}g/ml$ against hydrogen peroxide-induced oxidative stress in GC-2 spd (ts) cells. LPO were decreased significantly at 2.5, 5, 25 ${mu}g/ml$ of WNS concentrations. Catalase activity was significantly increased at 2.5, 5 and 10 ${mu}g/ml$ of WNS concentrations, respectively. Conclusions : In conclusion, WNS has antioxidant activities in GC-2 spd(ts) cells against oxidative stress.