The FAO AquaCrop is a dynamic crop water productivity model that simulates and partitions evapotranspiration during the growing season. Once transpiration is determined, the aboveground biomass is calculated using the user-input biomass water productivity parameter. This latter parameter, provided experimentally, is normalized for climate so that it can be extrapolated to other climatic zones. The objective of this study was to parameterize AquaCrop and evaluate its performance for irrigated cotton in the Mediterranean environment of Northern Syria. AquaCrop was parameterized using extensive in-season data from a drip irrigated cotton under a range of irrigation regimes (40 to 100 percent of full crop water requirements) and nitrogen applications at ICARDA research station in Tel Hadya, Syria for the 2006 cropping season. Parameterization was relatively straightforward within the designed user-interface, owing to the limited number of key parameters to be adjusted. The parameterized model was evaluated for the other irrigation and N treatments in 2006 and blind applications of the model were performed using the 2004 and 2005 data sets. The current version of AquaCrop does not simulate nitrogen dynamics, but stress was indirectly simulated using experimentally verified reduction in water productivity under suboptimal N applications. Measured water productivity (normalized for reference ET) ranged from 16 to 10 g/m2 for the 200 to 100 kg/ha N applications. Variations in crop water use (ranging from 400 to 900 mm per season) and water stress across the irrigation regimes were adequately captured by the model, which translated to sound predictions of biomass and yield. Results are particularly promising considering the simplicity of the model and the limited parameterization. The parameterized inputs for cotton performed satisfactorily at Tel Hadya, but need to be further tested under a wider range of climate and soil variability. Presentation will elaborate on key input parameters and model sensitivity.