AQUACROP (Steduto et al., 2009; Raes et al., 2009) simulation model was calibrated and validated for processing tomatoes in Southern Italy (Capitanata Plain) and was subsequently used to evaluate the expected impact of different water irrigation regimes on yield, water use effciency and net return. The simulated irrigation regimes were two: i) at Axed times (with seasonal water volumes of 170, 270, 370, 470 and 570 mm) and ii) using the soil water depletion criterion (refilling 30, 50 and 70 mm of soil water depletion). Cross calibration and validation, based on three years of experimental data (2002-2004), allowed to estimate crop parameters and their variation ranges, providing useful data which can be applied in similar environment conditions. The responses of the tomatoes in terms of plant biomass, fruit yield and water use effciency were evaluated considering the mean values obtained from a long-term simulation. A simplified economic analysis, was performed to calculate the net return for each management scenario. The greatest fresh fruit yield (123 t ha -1) simulated by AQUACROP was obtained using an irrigation Axed time with 370 mm of seasonal water supply. About the same yield level was obtained with irrigation starting at 30 mm of soil water depletion, saving of about 70 mm of water. The main advantage of soil water depletion criterion, apart from the low water loss in deep percolation, was the greater net income for farmers. Considering Axed irrigation turns, the net income oscillated between 1,280 € ha -1 and 3,420 € ha -1 for seasonal irrigation water amount equal to 170 and 570 mm, but with the highest income at 370 mm (4,011 € ha -1). Oscillation in net income for irrigation based on water depletion, were contained in a smaller range (from 3,467 to 4,137 € ha -1). Water use effciency for total dry biomass and fruit yield was similar among the two water regimes, while the irrigation water use effciency was heavily infuenced by irrigation strategy, with higher values in the soil water depletion scenarios. The case study allowed us to estimate a list of crop parameters useful for the adoption of the AQUACROP model in similar conditions. The criterion of starting to apply irrigation at a level of soil water depletion of 30 mm proved to be effective for fruit yield (high average and low yearly variability) and the effciency to convert the water available for the crop into biomass, reducing the water stress for the plants; moreover, it minimized water percolation in comparison to the Axed times application criterion.