In this study, an integrated modelling framework was assembled to investigate potential impacts of agricultural expansion and climate changes on irrigation water requirements in Taita Hills, Kenya. The framework comprised a land use change simulation model, a reference evapotranspiration model and synthetic precipitation data sets generated through a Monte Carlo simulation. In order to generate plausible climate change scenarios, outputs from General Climate Models were used as reference to perturbing the Monte Carlo simulations. The results indicate that the low availability of arable lands in the hills will drive agricultural expansion to areas with higher irrigation water requirements in the foothills.