Flax ( Linum usitatissimum L.) is an seed crops that its oil is used in different industries and as edible oil. Improvement of the seed and oil yield in flax is economically important and the genetic potential of adapted landrace varieties can be used in breeding programs. In order to investigate the genetic variability for the agronomic traits in landrace varieties of flax for single plant selection and isolating the breeding lines, this study was conducted at the research farm of Isfahan University of Technology, in 2005. A randomized complete block design with four replications was used Six landrace varieties collected from Khorasan, Kordestan, Shahreza, Ahvaz, Semirom, Chaharmahal Bakhtiary regions and the "Flanders" cultivar from Canada were evaluated to assess inter and intra-population variation of agronomic traits. There was a significant difference among the populations for all the studied traits such as capsules/plant, seeds /capsule, and 100-seed weigh. The genetic coefficients of variation was less or the same as the phenotypic coefficients of variation for most of the traits indicating that most of the variation for those traits was due to the genetic factors. The highest and lowest coefficient of variation was obtained for yield/plant and oil yield, respectively. The populations also showed a high variation for the studied traits among the single plants within the population. The highest intra population variation was observed for seed yield/plant and capsules /plant, however, the lowest variation was found for to 100-seed weigh. Capsules/plant had a significant and positive correlation with seed yield/plant, however, seed yield/plot had a high and significant correlation with days to maturity, capsules/plant and seed yield/plant. Oil yield had high and significant correlation with seed yield, but it had no correlation with seed oil content. The results of stepwise regression indicated that capsules/plant and seeds/capsule were the most important component of seed yield and capsules/plant, seeds/capsule and 100-seed weigh could explained 88% of the variation for seed yield /plant. The stepwise regression also indicated that capsules/plant, seeds/capsule and 100-seed weigh were the most important components of seed yield/plant in most of the populations. Based on path analysis, 100-seed weigh and plant height had more direct effect on seed yield/plot. But, capsules/plant had the most direct and positive effect on seed yield/plant. In conclusion, the existing genetic variation for most of the traits including the yield components indicated that selection can be effective to improve these traits and capsules/plant, seeds/capsule and 100-seed weigh can be used as selection indices to improve the seed yield.