The Eastern Nile Technical Regional Office (ENTRO), headquartered in Addis Ababa, Ethiopia, is one of the three centers of the Nile Basin Initiative , (NBI).  ENTRO was established in 2002, three years after the NBI.  ENTRO implements the Eastern Nile Subsidiary Action Program (ENSAP) for the member countries of Egypt, Ethiopia, South Sudan, and Sudan. ENSAP is one of the two Subsidiary Action Programs (SAPs) of NBI (the other being the Nile Equatorial Lakes Subsidiary Action Program).

ENTRO also provides secretariat support to the Eastern Nile Council of Ministers (ENCOM), the highest policy and decision-making body of ENSAP.

As a regional technical organization supporting the cooperative management and development of the common Eastern Nile water resources, ENTRO works on a range of areas including: water resources planning and management (including modelling); irrigation and drainage; flood and drought preparedness; forecasting and early warning systems; watershed development and management; power interconnection and power trade; dam safety; coordinated operations of a cascade of dams; social development, media and communication;  knowledge management and capacity building.

The Nile Basin Initiative (NBI) is an intergovernmental partnership of ten Nile Basin countries, Burundi, DR Congo, Egypt, Ethiopia, Kenya, Rwanda, South Sudan, The Sudan, Tanzania, and Uganda (Eritrea participates as observer). Established in 1999, the NBI seeks to develop the River Nile and associated resources in a cooperative manner, share substantial socioeconomic benefits, and promote regional peace and security. The Nile Basin Secretariat (Nile-SEC), headquartered in Entebbe, provides secretarial support and coordinates the implementation of NBI programs through two regional centres, the Eastern Nile Technical Regional Office (ENTRO), headquartered in Addis Ababa, Ethiopia and Nile Equatorial Lakes Subsidiary Action Plan Coordination Office (NELSAP-CU), headquartered in Kigali, Rwanda.