The main purpose of deficit irrigation is high water productivity with lesser water supplies to optimum crop yield. Accurate crop development models are important tools in evaluating the effects of different water applications on crop yields. The FAO-AQUACROP model (Ver. 5.0) simulates attainable yields of several crops as a function of water consumption under rainfed, supplemental, deficit, and full irrigation conditions. The aim of this study; validation and testing of the AQUACROP model for winter wheat under full and rainfed conditions in semi arid condition such as Central Anatolia. Model prediction and actual results were compared. According to statistical evaluation; average deviation (a), standard error (RMSE) and modeling efficiency (E) for biomass and for crop yield was found as 1.16, 1.17 t ha(-1) and 0.67 and 0.320, 0.326 t ha(-1) and 0.83 respectively. Model predicted soil water content in root zone, canopy cover and grain yields with high accuracy but biomass were predicted higher than actual results.