EAM-ELAS, communist-sponsored resistance organization (formed September 1941) and its military wing (formed December 1942), which operated in occupied Greece during World War II. Fighting against the Germans and the Italians as well as against other guerrilla bands, particularly EDES, EAM-ELAS became the most powerful guerrilla band in the country. It also established an effective administrative apparatus, through which it ruled liberated areas.
By October 1944, when the Germans evacuated Greece, EAM controlled about two-thirds of the country. It participated in conferences in September 1944 that were designed to unite the rival resistance groups and the government-in-exile in a postwar government. When the new government ordered ELAS to disarm, however, the resistance group refused, causing an outbreak of hostilities in Athens (Modern Greek: Athína) in December 1944, mainly between ELAS and the British. A peace treaty was signed (Varkiza Peace Agreement, Feb. 12, 1945), providing for the surrender of ELAS. A large-scale guerrilla war was begun by the communists in 1946, however, and lasted until 1949.