Recent violent conflicts in Africa have seen extensive use of very irregular armed forces by governments. Examples include the use of Kamajors in Sierra Leone, Janjaweed and other militias in Sudan and Interahamwe militias in the 1994 genocide in Rwanda. The paper, originally written for a seminar on Threatened Trust. The transformation of the state and fading civil security at the Centre for African Studies, Institute for Social Anthropology, University of Basel, Basel, 9-10 January 2006, analyses the historical background of such phenomena, the strategic benefits and drawbacks of the resort to such forces, the consequences for the conduct of armed conflicts and the implications thereof for the civilian populations. Finally, it points to a number of complications caused by the presence of such forces for peace settlements and post-conflict peacebuilding, including DDR (disarmament, demobilisation and reintegration) of former combatants and security sector reform.