Water shortage crisis is an issue that has led to drastic changes in different agricultural policies, especially in arid and semi-arid areas. Uncertainty in the amount of resources, e.g. water, used for agricultural production entails risk for farmers' income and cropping pattern changes. In the present study, the robust optimization model was used for optimal allocation of arable lands of Khorasan Razavi Province under uncertainty. During the allocation, the effect of water input price variations on total gross margin and cropping pattern was considered. It was found that under certain data, both parameters of total gross margin and total acreage are more than uncertain data. Given that water price variations resulted in tangible changes in wheat acreage, it is recommended to adopt appropriate policies to reduce its production risk.