This investigation was conducted to evaluate the effects of the osmopriming on seed germination of rapeseed, under water stress condition. The design of the experiment was a factorial completely randomized design (CRD) with three replications. The experimental factors were three rapeseeds cultivars, (Cobra, SImo46 and Okapi), three levels of Osmopriming (0, -3, -6, -9, -12 and -15 bar) and three levels of water stress (-5, -10 and -15 bar). At the first stage seeds were immersed in one level of Osmopriming treatment for up to 48 hours at room temperature. Then the seeds were distilled by water for 24 h at 30°C and subjected to water stress treatments for two week. The results showed that Osmopriming technique had a significant effect (p<% 1) on seedling parameters including: dry weight of seedlings, length of radicles and plumules, rate and period of germination. The upper levels of osmopotential had more inhibition effect on plumula growth than the lower levels of osmopotential. Means comparing showed that the most and least rate of germination was obtained by Okapi and Cobra hybrids, respectively. Under water stress conditions Okapi hybrid had longer radicle, more lateral roots and higher proportion of root to plumule then the other cultivars. Thus this cultivar was more resistance ant to water stress.