Effects of ambient and elevated ~textrmCO2 and high temperature, and their interactions with zero and applied nitrogen supply (NN-no nitrogen and AN-applied nitrogen) were studied on soybean (Glycine max L.) in 2001. In this experiment, elevated ~textrmCO2 (650 ~mu~textrmmol.~textrmmol-1 ) and temperature (+5~circ ) increased total dry mass at final harvest by 125% and 119% and seed weight per plant by 57% and 105% for NN and AN plants, respectively. Although the influence of temperature and temperature x ~textrmCO2 were not significant, the influences of ~textrmCO2 concentration and temperature x ~textrmCO2 concentration were significant on total dry weight and seed weight, respectively. In particular, seed weight per plant was increased, while weight per one hundred seed weight was decreased with elevated ~textrmCO2 and temperature. The N supply increased biomass and seed weight per soybean plants. The results of this study suggest that the long-term adaptation of soybean growth at an elevated ~textrmCO2 concentration and high temperature might potentially result in a increase in dry matter production and yield.