The Indus, Ganges and Brahmaputra river basins support 700 million people in Asia. The water resources are used for irrigation, drinking, industry, navigation and hydropower. This paper reviews the literature on the impact of climate change on the hydrological regime of these river basins and suggests that the different basins are likely to be affected in different ways. Climate change will have a marked affect on meltwater in the Indus Basin and may result in increased flood risk in the Brahmaputra Basin. The overall impact on annual discharge is likely to be low, but more studies are required to understand intra-annual changes and the impact of extreme events.