Tomato plants are fairly resistant to moderate drought. However, proper management is essential to assure high yield and quality. The water requirement of outdoor grown tomatoes varies between 4000 - 6000 m³/ha. In greenhouses up to 10,000 m3/ha of water are required. 70% or more of the root system are in the upper 20 cm of the soil. Therefore, a drip system equipped with a fertigation device is advisable. On light soils or when saline water is used, it is necessary to increase water quantities by 20% - 30%. Water requirements will differ at various growth stages. The requirement increases from germination until beginning of fruit setting, reaching a peak during fruit development and then decreasing during ripening. Mild water stress during fruit development and ripening has a positive effect on fruit quality: firmness, taste and shelf-life quality, but may result in smaller fruit. Late irrigation, close to harvesting, may impair quality and induce rotting.