In order to develop winter cultivation and improvement rotation program of region, an experiment was conducted to evaluate the effects of sowing date on sunflower cultivars seed yield, as split-plot based on completed randomized blocks design with four replications in Safiabad Agricultural and Natural Resources Research and Education Center of Dezful during two years (2015-2016). The main plots were consisted of 4 sowing date levels (23rd Jan, 6th Feb, 20th Feb and 6th Mar) and sub plots included 9 levels of cultivars (Azargol, Armavirski, Barzegar, Progress, Record, Shams, Farokh, Ghasem and Gabor). Delaying in sowing date led to decrease growth period length and plant height. The highest number of seeds per capitulum (684.17) belonged to Record cultivar in the first sowing date in the first year and the maximum one (767.47) appointed to this cultivar in the third sowing date in the second year. The maximum seed yield in the first (3850 kg.ha-1) and second (4088 kg.ha-1) year appointed to the first sowing date (23rd Jan) and Azargol cultivar. Considering results, Azargol cultivar had the lowest rank and known as the cultivar had the highest seed yield at all sowing dates then Record and Armavirski,were placed respectively. In terms of stability, considering that Farrokh cultivar also had the lowest standard deviation, it was selected as the most stable cultivar.