This study investigates determinants of collective action among Nile Basin countries. It will be useful to national leaders in crafting a new Nile River Agreement, and policy makers and scholars involved in water issues. This study examines how the demand for water in the Nile Basin has reached a critical point which Egypt, the main player, cannot ignore. It also investigates how the past collective action had failed, partly, due to weak international laws. Today evolving international legal norms are influencing changes in multilateral cooperative behaviors among Nile Basin states. Although in the past funding any water related projects has been difficult in the Basin, recent changes in World Bank policies and the willingness of donors to commit is encouraging cooperation among members of the Nile Basin Commission.