To investigate the possibility of winter lentil grown under rain fed conditions and Comparison with conventional planting (spring) and determine the appropriate seeding density in each planting seasons this research in the city of Khorramabad 2008-2009 was administered. Experiment with two planting seasons (winter and spring) and seed density at five levels (200, 250, 300, 350 and 400 seeds per square meter), which were evaluated of factorial in a randomized complete block design with four replications. Trait measured were two seeds pod, single seedpods, total seed per unit area, seed yield, biological yield, harvest index(HI). Analysis of variance showed that the effect of planting date was significant on all traits. Seed yield, biological yield, harvest index, and number of seeds per unit area in autumn sowing were significantly higher than spring planting. The effect of planting density was significant on seed yield, seed number per unit area single seed pod. The maximum seed yield with 1600 kg/ha related to winter planting. Treatment of 350 seeds per square meter had the highest seed yield (1575 kg/ha).
