In order to evaluate the effect of seed aging on emergence and growth properties of sunflower cultivars a factorial field experiment was conducted based on Randomized complete block design with four replications. Experimental treatments included three sunflower cultivars (Haysan 25, Progress and Lakomka) and seed aging as senescence acceleration in five levels (control, 24, 48, 72, 96 hours) in 43˚C and relative humidity of 100%. Results of variance of analysis showed that the effects of cultivars were significant on emergence rate and final germination percentage at 1% level. While the effects of deterioration × cultivar were significant on only final emergence percentage, at 1 % level. As aging period increased emergence percentage decreased significantly for all three cultivars. Also, for each hour increase in deterioration, the emergence uniformity was enhanced up 0.239 hours. Mean comparison among the different cultivars showed that Haysan 25 and Progress had the highest and lowest emergence speed respectively. Also effect of seed deterioration and cultivars were significant on leaf dry weight, stem dry weight and seedling dry weight in the first and second stages of harvest. But the leaf number affected by seed deterioration at 1% level. Interaction of deterioration and cultivars were not significant on any traits at two harvest stages. Therefore based on experimental results, progress cultivar was the most sensitive cultivar to deterioration.