Two field experiments were carried out at the Agricultural Experimental Station of National Research Centre at Shalakan (Kalubia Governorate) during two successive seasons of 1996/97 and 1997/98 to study the effect of water stress (omitting one irrigation either at flowering, pod formation or pod filling stages) on three faba bean cultivars (Giza 3, Giza 643 and Giza 714). The results indicated that water stress at any studied reproductive stage showed harmful effects on yield and its components. The adverse effect of water stress was more pronounced whenever drought conditions were coincided with pod filling stage. Generally, the exposure to water deficits decreased significantly the total carbohydrate content in faba bean seeds, whereas an inverse relationship was noticed as for the protein content. On the other hand,  significant differences was found among the tested faba bean cultivars with respect to yield and its components as well as the chemical composition of seeds. Giza 643 cultivar produced the highest seed yield which characterized by a conspicuous content of crude protein compared with the other two cultivars. However, the differences were not distinct enough to use as an index of the drought resistance of the cultivars tested.