On the basis of literature and original sources the author describes the role of the combat and of the armed forces of National Liberation Movement in the years 1941—1945, further the role of internal structure of the partisan army, as well as relations between the civil and the military division of the movement. He also presents its main military achievements. The National Liberation Movement created extensive and organized armed forces, which were the independent part of the Yugoslav partisan army. The proportion between both of them moved during the war towards the armed forces unification and resulted in the Yugoslav Army formation and the Slovene partisan army disbandment.