The effect of irrigation on tomato yield depends on the actual weather conditions, basically the air temperature and precipitation (quantity and dispersion). The irrigated plants gave a significantly higher yield, and rainfed plants showed a yield loss. The optimum water supply treatment gave a significantly higher proportion of lycopene than the control (rainfed) treatment (89% and 80% respectively) in case of Brixsol F1 variety. In spite of this we have not found significant difference in case of Strombolino F1 (cherry type). Content of total poly-phenols measured in Strombolino F1 (cherry type) was significantly higher than that found in the Brixol F1 (normal type). The optimum water supply treatment resulted in a significantly lower content of total polyphenols in both years. Tomato fruits are rich in polyphenols the largest amount of which is rutin from among the identified components.