Environmental stresses specially drought, play an important role in decreasing plant growth, particularly during germination in dry and semi dry area. To considering the effect of drought stress caused by polyethylene glycol on germination and characteristics of 2 spices of Sesamum indicum, we had done factorial and complete accidental plot with 4 treatments and 3 times repetition. Experimental treatments included osmotic potential in 4 levels (0, -4, -6, -10 bar) which was produced by polyethylene glycol 6000 and 2 sesame species (Safi Abadi and Dezfol). All data had been analyzed by SAS software and comparison of means had been done by Duncan test at 5% probable level. The results showed that, percentage and speed of all spices’ germination decline by osmotic potential enhancement. Other measured parameters such as radicle and coleoptile length, dry and wet weight declined by increasing osmotic potential as well.