This study was carried out to evaluate the agronomic traits of the breeding lines isolated from the sesame landraces. Seventy genotypes were evaluated in randomized complete block design with two replications at the research farm of Isfahan University of Technology in 2008. In this research, the traits of days to emergence, days to flowering, days to maturity, branches per plant, plant height, capsules per plant, seeds per capsule, seed weight, seed yield per plant and seed yield per plot were evaluated. The oil content was also determined for 10 superior genotypes for seed yield. The results showed that there were significant differences among the genotypes for all of the studied traits. The highest coefficient of variation was found for branches per plant and the lowest for days to 50% flowering. There was no much differences between the phenotypic and genetic coefficients of variations for most the traits and it was concluded that the most of the phenotypic variations was due to the genetic factors. The seed yield per plot ranged from 1089 kg/ha to 4650 kg/ha (for Ahvaz- 11 breeding line). A breeding line isolated from Birjand landrace has the most days to maturity (170 days) and Yekta genotype had the lowest means of this trait (118 days). The range of plant height among genotypes was 123 to 179 cm. The mean of capsule per plant was ranged from 46 (TN- 240 genotype) to 181 (Ahvaz- 6 genotype). Branches per plant had the highest broad-sense heritability (81/1 %) and days to emergence had the lowest (35/2%). In this study, the number of capsules per plant showed the highest correlation with seed yield per plant. Based on the results of stepwise regression, number of capsules per plant, number of seeds per capsule and seed weight explained 79% of the variation for seed yield per plant. The results of path analysis showed that, capsules per plant had the most direct and positive effect on both seed yield per plant and seed yield per plot. The most indirect positive effect on seed yield per plant was observed for seeds per capsule via capsules per plant. It seems that number of capsules per plant, number of seeds per capsule and seed weight can be used as useful selection criteria to improve the seed yield in breeding program of sesame. Key word: genetic variations, Agronomic traits, Sesamum indicum