Water is the most precious agricultural resource in the water-limited environments. In order to determine seed yield, biological yield and harvest index of barley's cultivars in different treatments of drought stress, an experiment was conducted as a split plot arrangement based on randomized complete block design with four replications at experimental agriculture farm of Islamic Azad University, Khorasgan (Esfagan) branch, in Esfahan. Irrigation treatments as a main plot were arranged on the basis of evaporation from pan evaporation (including irrigation after 80, 100 and 120 mm evaporation from pan), and sub-plots included four cultivars (Fasih, Nosrat, Reihan 03 and Yosef). The irrigation was done normally from plantation until the beginning of reproductive stage. Irrigation and cultivar, both had significant influence on the number of spikes per m(2), the number of seeds per spike, 1000-seed weight, seed yield, biological yield and harvest index. The number of seeds per spike and harvest index were significantly affected by irrigation and cultivar interaction. The maximum number of spikes per m2, the number of seeds per spike, 1000-seed weight, biological yield and harvest index were obtained in irrigation on the basis of 80 mm evaporation from evaporation pan. Reihan 03 also obtained the maximum number of spikes per m(2), seed yield and harvest index. It seems that cultivation of Reihan 03 and irrigation on the basis of 80 mm evaporation from evaporation pan is suitable for this region.