Field experiments were carried out to evaluate the effects of four seed size (large, medium, small, and very small) and five plant populations (12.5, 25, 50, 100, and 150 plants m-2) on local faba bean yield and yield components. A split plot design with three replications was used, in which plant populations were assigned to main plots and seed size to sub plots. Sin seeds significantly increased seed yield during the first growing season (248 mm), whereas seed size did not have any effect in the second growing season (292 mm). Plants originating from very small and small seeds were faster in emergence, earlier in flowering, in podding, in maturity, and gave the highest harvest index values, which positively influenced seed yield However, large seeds were more sensitive to the adverse seasonal conditions such as drought and low temperature. Highest seed yield was obtained at 12.5 plant m-2 in the second growing seasons, but in the first growing season the greatest seed yield was obtained at 25 plants m-2, and further increase in the plant population density did not resulted in more increases in seed yield. Results indicated that the highest yield was obtained from planting small seeds at a density of 25 plants m-2. Small se produce substantially good yield over a range of seasonal conditions because it can apparently flower earlier, set pod efficiently, complete its reproductive growth quickly, and fill seeds efficiently.