Latent heat of evaporation represents a large outgoing component of the energy balance established at a crop-stand surface. This explains why agriculture uses approximately 70% of all the freshwater withdrawn in the world. Increasing demand for water due to population growth, competition with industrial, domestic and environmental requirements, and the decreasing quality of water, limit the agricultural capacity for food production. The Water Resources, Development and Management Service (AGLW) of the Food and Agricultural Organization of the United Nations (FAO) is carrying out activities aimed at helping country members in supporting sustainable water management to securing food for a growing population. These activities cut across the various levels of the water domain, going from the (inter)national policy level down to local-level field applications. In this article, FAO's experiences in agricultural water management are used to provide lessons from the past and indicate directions for future challenges.