Abstract: This study aims to determine the guerrilla struggle of the BeruangHitam troops in defending Lampung so that it remains part of the independent Republic of Indonesia. This research is a qualitative research with historical methods and data collection techniques using the literature techniques, documentation, interviews with descendants of Abu BakarSidiq and the former of BeruangHitam troops. The results of this study indicated that the BeruangHitam paramilitary was a defense force for the country whose members consisted of ALRI (Navy of the Republic of Indonesia), the People and in their struggle several TNI asked to join. BeruangHitam troops decided to carry out a guerrilla warfare strategy because of the bigger enemy force and unbalanced weaponry so that it was impossible to carry out an open warfare, besides Lampung geographic which was mostly forests, hills and mountains, it was very possible to use a guerrilla war strategy. The guerrilla war of BeruangHitam troops spread throughout Lampung, namely: Lampung Selatan, Gedong Air, Kemiling, Sukadanaham, Way Lima, GunungSugih, Metro, and Lampung Utara. BeruangHitam troops had a major contribution in defending Lampung and succeeded in maintaining the residency of Lampung in Bukit Kemuning, Lampung Utara. Before carrying out the attack, the BeruangHitam troops always prepared the war strategies, defensive strategies and attack techniques which were the key to success in every battle.