Every potential stress factor, abiotic or biotic, which goes beyond the optimal values for the growth and development of plants, represents stress. One of the most stressful abiotic factors is water stress that poses a significant problem in the plant cultivation. It is usually caused by high salinity of the soil, thermal stress, cold, freezing and the most common of all - drought. Wheat and tomato, as the most common agricultural plant species, represent a useful model for studying the impact of the drought on plants. The aim of this study was to examine the impact of drought on physiological indicators in wheat and tomato, and to study the role of zeolite (mineral additive with the ability to absorb water and nutrients) in water retention and defense of the plants during the drought. Plants were grown in the substrate without zeolite or in the substrate with zeolite, in varying granulations and percentages, in control and water stress conditions. The results showed that the water deficit desreased plant growth and water content, but increased concentration of proteins, proline and lipid peroxides. Activity of catalase was lower in wheat exposed to drought while no significant differences was observed in guaiacol peroxidase activity between control plants and plants exposed to drought. In most of the investigated parameters there were no differences between plants grown on substrates, with or without the addition of zeolite, irrespective of the extent and granulation of the zeolite.