Maize (Zea mays), is a plant of economic and nutritional interest, which is often confronted with unfavorable environmental conditions, including water stress. This phenomenon forces the plants to considerably reduce their production by disturbing their metabolism. Seeds of maize of the variety EV8728 were subjected to different doses of gamma radiation (100, 200 and 300 grays) in order to induce mutations in plants that could lead to resistance to water stress. Thus, plants from gamma irradiated seeds were used to evaluate the impact of water stress on leaf physiological parameters (leaf area, density and pore area of stomata and assimilatory pigments). Water stress had a depressive effect on all leaf parameters in maize plants. The degree of sensitivity or tolerance of the plants depends on the dose of irradiation and the intensity of stress applied. The increase in the level of water stress reduces the leaf surface and that of the stomata pores. This in turn increases the density of stomata. In addition, chlorophyll a was more sensitive to the effect of water stress than chlorophyll b.