The aim of this article is to analyse legal aspects of armed resistance movements with a focus on the legal status of the partisan and the legal nature of a civil war. In the light of the norms of international law, both the status of a partisan and the nature of a civil war is, from the point of view of this analysis, connected with, inter alia, international recognition and military occupation, which constitute a significant part of the investigations in this article, synthetically analysing the activity of the Polish resistance movement against the illegal communist rule after 1945 (the so-called "cursed soldiers"). Apart from the analysis of international and domestic legal norms and their interpretation, the article refers to the history of the evolution of the legal status and the theory of the partisan.