After the cereal grains, the oil seeds are the second source of energy in human diets and also their oil meal that obtained after oil extraction are valuable source of protein to be used as a feed for livestock and poultry. The increase of demand for vegetable oils in the world market have caused to be paid more attention to oilseed production and expanding the research programs for these crops. In order to study the genetic variation for improving agronomic traits and seed yield in sesame, 28 genotypes of this crop were planted and evaluated in a randomized complete block design with three replications at the research farm of Isfahan University of Technology in 2015. In this study, the traits of days to 50% emergence, days to 50% flowering and maturity, plant height, branches/plant, capsules/plant, seeds/capsules, seed weight per capsule, 1000- seed weight, seed yield/plant, seed yield per plot were measured. The results of analysis of variance showed that there were significant differences among the genotypes for all of the studied traits, except for days to 50% emergence. Seed yield/plot of the genotypes varied from 229 kg/ha for TN240 to 1933 kg/ha for genotype Shiraz 8. Genotype of Jiroft had the highest mean of days to maturity (123.6 days) and Tn240 with 106.6 days had the lowest mean of this trait. The phenotypic coefficients of variation were greater than the genetic ones for all the traits, but their differences were so small for most of the traits.The highest phenotypic and genetic coefficients of variation were obtained for branches/plant and the lowest ones for days to 50% emergence. Capsules/plant and seeds/capsule had positive and significant correlation with seed yield/plant. Also, capsules/plant and seed yield/plant highly correlated with seed yield/plot. The results of stepwise regression showed that capsules/plant, seeds/capsule and 1000-seed weight were in order the important components of seed yield/plant and they explained 80% of its variation. The results of path analysis indicated also that capsules/plant had the greatest direct and positive genetic effect on seed yield/plant. In general, the results of this study showed that there was high genetic variation among the genotypes of sesame for all of the studied traits and selection can be effective to genetically improve those traits. In order to improve seed yield of sesame in breeding programs, capsules/plant, seeds/capsule and seed weight can be considered in order of importance as the selection criteria. Key word : Sesame, Genetic variation, Agronomic traits. Seed yield, Yield components