Since October 2001, bio‐agent risk has become a high priority threat factor and one of the key issues of the national and international anti‐terrorist activities. The presentation is going to summarize known microbial agents in accordance with their potential or suitable for being used as biological weapons, and also the hazards or burdens attributed to the proliferation of such weapons or their bioterrorist use. Consisting mainly of natural pathogens, at this time various lists are known from different sources aiming to categorize microbial agents for this respect. Since 2001 WHO and CDC bio‐agent classifications have become the most acknowledged and widely used ones. Such systemic collections of pathogens combined with the specific risk estimation viewpoints are not only theoretically useful for preventive military medical purposes, but it can directly and successfully assist NBC defence practices, too. Although in the era of genomics the real value of any lists is rather limited, yet they can provide useful references and practical guidance to the medical aspects of force protection planning, as well as for the entire spectrum of medical defence activities and efforts, including the development of newer and more efficient decontamination procedures.