In order to investigate the effect of planting dates on the yield of three new corn hybrids, an experiment was carried out during the summer of 2003 in Safiabad Agricultural Research Center. This experiment was conducted as a split plot design in complete randomized blocks with four replications with three levels of planting dates as main factors and four cultivars as sub factors. Planting dates were achieved in July, 13 and 23 and August, 2 on 2003, Sub plots were included four corn hybrids SC4-S 3393, SC4-S 3282, SC4-S 3261 and SC 704 as a check. Results showed that planting dates had a significant effect on the yield of corn hybrids. The differences of yield measurement also indicated that planting dates × hybrids interaction was significant at the 5% probability When mean comparisons were used to test for treatment differences showed that the highest yield with 11310 kg seeds/ha was obtained on sowing date of July twenty third, while the lowest yield with 8065 kg seed/ha occurred in July thirteenth when the interaction effect was evaluated in associated with treatments, it has shown that SC4-S 3393 and SC4-S3261 which were planted at the different planting dates (July, 23 and July 13) had the highest (12430 kg seeds/ha) and the lowest (6689 kg seeds/ha) yield, respectively.