"One of the most important wheat breeding strategies under Mediterranean climate is to achieve genotypes that are potentially capable of producing desirable yield while encountering water limitation during their flowering stage. In order to identify traits effective on the yield and determine the best and most efficient drought tolerance indices for bread wheat in cold region of Ardabil, an experiment was conducted on 12 bread-wheat genotypes (treatment) based on complete randomized block design with three replications at experimental farm of Islamic Azad University, Ardabil Branch, in 2010. Examination of drought tolerance indices revealed that indices such as STI, GMP and MP were highly correlated with Yp and Ys, which were designated as the most efficient indices. Moreover, genotypes such as Tous and 4041 by producing the highest yield were the most tolerant genotypes. By analyzing to main components based on drought tolerance indices, the two main components accounted for 99.54% of the variations. Saratovskaya-29 was identified as the weakest genotype in the region both at stressed and normal conditions."