Access to safe water and basic sanitation has become a serious problem in Indonesia. The activities supported by the Dutch in the water sector in Indonesia aims to assist the process of integrated water resources management in order to reform the water sector which was implemented in 2004 and to help achieve the Millennium Development Goal on access to safe water and sanitation (MDG Target 7C). This research is aimed to describe about the cooperation between Indonesia and the Netherlands on water supply and sanitation in Indonesia; to describe the objectives of the cooperation; to illustrate the Netherlands interest in conducting the cooperation with Indonesia; and to describe the future of the cooperation on water supply and sanitation in Indonesia. The researcher uses descriptive method with a qualitative approach in describing the cooperation on water supply and sanitation in Indonesia. Several concepts have been used such as liberal theory, foreign policy, international cooperation, decision-making process, non-zero sum game, economic and social development, and water and sanitation management.