Abstarct: In fact, planting arrangement and plant density should be adjusted in such a way that intra- and extra-species competition is minimized so that plants can use the available growth factors well. Different sesame numbers have different growth characteristics and therefore each one is probably suitable in general for a cropping system and specifically for a planting method and with a specific density. Therefore, this experiment was carried out during the year 1400 baxsed on the experimental design of the chopped plots in the form of a randomized complete block design in three replications, in which the experimental treatments were the distances between the planting rows of 30, 40 and 50 cm as the factor of the main plot and commercial cultivars. Susceptible to seed loss (including Eltan, Naz Chandkholi, Darab 2, Dashestan 2, Halil), relatively tolerant genotype to seed loss (including G.KARA117) and genotypes tolerant to seed loss (G.KARA0, G.KARA24 and G. KARA42) were considered as sub-factors. The results showed that the phenology of sesame was not affected by the cultivation interval, but all the phenological stages, except the number of days until the beginning of seed development and the length of the aging period, had significant differences between cultivars, which can be attributed to the genetics of different cultivars. Also, according to the obtained results, it was found that Halil cultivar was the lateest and Ultan cultivar was the earliest among the tested cultivars. The results of the present study showed that the phenological traits were only affected by the variety and the planting density had no effect on the phenological traits. On the other hand, the results showed that the effect of density and cultivar had an impact on the morphological traits and yield and yield components of sesame. Also, the results showed that traits such as the number of capsules per plant, the number of seeds per capsule, and the weight of 1,000 seeds increased with the increase in planting distance, but the seed yield, biological yield, and harvest index decreased. The results related to the mutual effect of row spacing and variety on sesame seed yield showed that the highest seed yield with an average of 3496.89 kg was related to the G.KARA24 variety, which did not show a significant difference with the G.KARA42 variety with an average of 3296.89. In general, the results showed that in all tested cultivars, the row spacing of 30 cm is the most appropriate planting distance.