The objectives of this study were to investigate the genetic variability for the agronomic traits in landraces of sesame and select single plants for isolating the breeding lines. This study was conducted at the research farm of Isfahan University of Technology in 2006. A randomized complete block design with four replications was used to evaluate seven landraces of sesame from the regions of Ardestan, Ahvas, Birjand, Shiraz , Golpayegan, Markazi and Mobarake to assess inter and intra–population variation for agronomic traits. The studied characters were days to flowering, days to maturity, plant height, percentage of lodging plants, branches/plant, capsules/plant, seeds/capsule, 200- seed weight, seed yield/plant, seed yield/plot, seed oil content and oil yield/plot. The results showed significant differences among the landraces for all of the studied traits. The phenotypic coefficients of variation were greater than the genetic ones for all the traits, but their differences were so small in most of the traits. The highest phenotypic and genetic coefficients of variation were obtained for branches/plant and the lowest for 200–seed weight. The variation among single plants within the populations was also high for the studied traits. The highest intra-population variation was observed for branches/plant and the lowest was found for plant height. Capsules/plant and seeds/capsule had high and positive correlation with seed yield/ plant. Capsules/plant and seed yield/plant also highly correlated with seed yield/ plot. Oil yield had high and significant correlation with each of seed yield and seed oil content. Stepwise regression showed that capsules/plant, seeds/capsule and 200-seed weight were important components of seed yield/ plant and explained 92% of its variation. Capsules/plant, 200–seed weight and seeds/capsule were also in order more important components of seed yield/plot. The stepwise regression also showed that in landraces of Ardestan, Golpayegan, Markazi and Shiraz , capsules/plant was the most important component of seed yield/ plant; however in Mobarakeh and Ahvaz landraces, 200- seed weight and seeds/capsule were the most important components of seed yield/plant, respectively. Results of path analysis indicated that 200–seed weight had the greatest direct and positive genetic effects on seed yield/ plant and seed yield. In general, the results of this study showed that there was high genetic variation between and within landraces of sesame for all of the traits and selection can be effective to improve the 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