We assessed the environmental risk of herbicide resistant transgenic rice (Protox) on non-target herbivore, grasshoppers (Oxya japonica japonica Thunberg). We conducted life-history experiments of grasshoppers with measuring their body weight, body length, eating amount, and feces amount between non-transgenic rice (nTR; Dongjin rice) and transgenic rice (TR; Protox rice) under laboratory conditions (Temp. 25Ð, R.H. 50-70%, Photoperiod L16:D8) in 2007. The growth of grasshoppers appeared to increase at each measuring date. We also compared the growth rate of grasshoppers between nTR and TR to examine the transgenic impact on the herbivore and we found there was no statistically signifi cant difference between the two plant types (P>0.05). We found that body weight and body length for grasshoppers were highly correlated at each of the two types of plants, nTR (0.962) and TR (0.960). The correlation of eating amount and feces amount of grasshoppers were higher nTR (0.830) than TR (0.782). The energy effi ciency of the grasshopper was not a signifi cant between nTR and TR (P> 0.05). But the molt timing of the grasshoppers for TR difference was faster than for nTR. Conclusively life-history of the grasshoppers but molt timing was not a signifi cant difference between nTR and TR. Therefore, we could conclude there was not any environment risk on herbivore from our result.