This study was carried out in order to determine the effect of seed size on the yield and yield components of chickpea and lentil. Two field experiments, composed of three chickpea (Cicer arietinum L.) varieties, four lentil (Lens culinaris Medik.) and two seed sizes, were conducted in southeastern Anatolia, Turkey in 2005 and 2006 in randomized complete block designs. The seeds of the three grading sizes used in this study were evaluated for yield and its components in chickpea and lentil. Forchickpea, effect of seed size on yield and 100 seed weight were significant, but no difference in seed size affects other yield components, and correlations between seed size and seed yield and 100 seed weight were positive. For lentil, effect of seed size on yield and yield components was not significant.