This article examines four accepted wisdoms about HIV/AIDS and African armies and in each case concludes that substantial revision is necessary in the light of emerging evidence. First, it appears that military populations do not necessarily have a higher prevalence of HIV than civilian populations. HIV levels in armies depend on many factors including the demographics of the army, its pattern of deployment, the nature and stage of the epidemic in the country concerned, and the measures taken to control the disease by the military authorities. Second, although the epidemic has the potential to undermine the functioning of national militaries, and may have done so in isolated instances, armies in general are well placed to withstand the threat. Third, evidence that war contributes to the spread of the virus is meagre and suggests that we should be concerned primarily with specific risks that conflict may entail including population mobility and changing sexual networks. Lastly, the hypothesis that AIDS has the potential to disrupt national, regional, and international security remains speculative. © 2006 Oxford University Press.