Effects of ambient and elevated $ extrm{CO}_2$ 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 $ extrm{CO}_2$ (650 $mu extrm{mol}. extrm{mol}^{-1}$) 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 $ extrm{CO}_2$ were not significant, the influences of $ extrm{CO}_2$ concentration and temperature x $ extrm{CO}_2$ 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 $ extrm{CO}_2$ 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 $ extrm{CO}_2$ concentration and high temperature might potentially result in a increase in dry matter production and yield.