When the African nationalist revolt erupted in early 1961, the Portuguese army in Angola numbered about 8,000 men, 5,000 of whom were African. The colonial forces responded brutally, and by the end of the summer they had regained control over most of the territory. The humÍÍÍÍan cost, however, was enormous: more than 2,000 Europeans and up to 50,000 Africans died, and about 10 percent of Angola's African population fled to Zaire. By early 1962, the Portuguese army in Angola had grown to 50,000 and thereafter averaged 60,000 into the mid-1970s. About half of this expansion was achieved by conscription in Angola, and most conscripts were Africans. The Portuguese established a counterinsurgency program of population resettlement throughout the country. By the mid-1970s, more than 1 million peasants had been relocated into strategic settlements, and 30,000 males had been impressed into service in lightly armed militia units to defend them.

The thirteen-year Angolan war for independence, in which three rival nationalist groups fought the Portuguese to a stalemate, ended after the April 1974 military coup in Portugal. At that time, the MPLA and the FNLA had an estimated 10,000 guerrillas each, and UNITA had about 2,000. Within a year, these groups had become locked in a complex armed struggle for supremacy. By November 1975, when independence under a three-way coalition government was scheduled, the MPLA and the FNLA had built up their armies to 27,000 and 22,000, respectively, while UNITA had mustered some 8,000 to 10,000. Further complicating the situation was a substantial foreign military presence. Although the Portuguese forces numbered only 3,000 to 4,000 by late 1975, some 2,000 to 3,000 Cubans had arrived in support of the MPLA, from 1,000 to 2,000 Zairian regulars had crossed the border to aid the FNLA, and 4,000 to 5,000 SADF troops had intervened on behalf of UNITA. The civil war was soon decided in favor of the MPLA by virtue of the massive influx of Soviet weapons and advisers and Cuban troops.

Data as of February 1989