This study was carried out to evaluate the effects of drought stress on 12 genotypes of vetch (Vicia dasycarpa) at the experimental field of Agriculture and Natural Resources Center of East Azarbaijan Province during 2003. Field trial was conducted as a spilt plot design based on randomized complete blocks with three replications. Drought treatments (normal, medium and severe stress conditions) were included in main plots and the genotypes were allocated in subplots. During the growing season, plant height, pod length, pod width, number of grains per pod, 1000 grain weight, number of pods per plant, number of grains per plant, number of axillary branches, harvest index, biomass and grain yield were measured. Drought stress effected all traits (except number of grains per pod) significantly. Greatest amount of reduction in value due to water stress belonged to grain yield and biomass. Number of pods per plant and number of grains per plant were affected by drought more than other yield components. However, the adverse effect of water stress was not similar for all genotypes and there were significant genotype by environment interaction for important characters such as biomass, grain yield, number of pods per plant, number of grains per plant and plant height. Evaluation of the genotypes based on drought tolerance indices (STI and TOL) indicated that under medium water stress environment the genotypes 9 (from Italy) and 7 (from Turkey) showed better drought tolerance performance in terms of grain yield. Regarding biomass, the genotypes 3 (from Italy) and 6 (from Australia) were recognized as the most appropriate genotypes for hoth medium and severe drought stress conditions.