In order to evaluate effects of drought stress on yield and yield components of soybean (Glycine max L.), an experiment was conducted in the research field of the Islamic Azad University of Kermanshah, Iran at 2009. Responses of eight soybean cultivars at two separate experiments (normal and stress sites) were investigated based on randomized complete block design with three replications. The results were shown that except number of sub branch in stress site and 100-seed weight per plant in normal site other traits affected by cultivar effect. Cultivars had significantly differences in number of sub branch and 100-seed weight in main stem in normal site at 5% levels and other traits in both trials at 1% levels. Means comparison was shown that Williams cultivar had the highest number of node/plant, number of pod/main stem, pod/sub stem and pod/plant in normal and stress conditions. In normal site, Clark cultivar had the highest value of number of sub branch, and superiority to other cultivars. The highest and lowest number of seed/main stem, seed/sub stem and seed/plant was observed in Williams and Hood cultivars, respectively. Decrease in seed yield in stress site compared normal conditions recorded about 43-44%.
