The Southeastern Anatolia Project (GAP) is an integrated socioeconomic development project and one of the largest of its kind in the world. The GAP region is rich in water for irrigation and hydroelectric power. The Euphrates and Tigris rivers represent over 28% of the nation's water supply by, and the economically irrigable areas in the region make up 20% of those for the entire country. Turkey has a total gross hydropower potential of 433 GWh/yr, but only 125 GWh/yr of the total hydroelectric potential of Turkey can be economically used. By the commissioning of new hydropower plants, which are under construction, 36% of the economically usable potential of the country would be tapped. The GAP region has a 22% share of the country's total hydroelectric potential, with plans for 22 dams and 19 hydroelectric power plants. Upon the completion of the project, 1.7 million ha of land will be brought under irrigation, energy production in the region will reach 27 billion kWh, per capita income will rise by 209% and about 3.8 million people will be provided employment opportunities. This article discusses the contribution of the GAP to irrigation and hydroelectric power production in Turkey.