Disease can be caused by various species of the genus Mycobacterium. A number of reports, both published and unpublished, of rarely reported mycobacteria have surfaced in South Africa in the last few years. Some unusual hosts have also been involved, causing concern in some quarters.These include reports on Mycobacterium goodii in a spotted hyaena (Crocuta crocuta), M. xenopi in a ruffed lemur (Varecia variegata), M. intracellulare in wild-caught chacma baboons (Papio ursinus), the 'dassie bacillus' in free ranging rock hyrax (dassies; Procavia capensis) the 'oryx bacillus' from free-ranging buffalo (Syncerus caffer) and M. tuberculosis in suricates (Suricata suricatta), a domestic dog and in baboons. In this article it has been attempted to put these in context and show how improved surveillance and technologies have allowed mycobacteria to be identified to species level more easily. Most of the unusual mycobacterial species have most likely been present in the region for many years and have probably caused disease episodes before, but have been misdiagnosed. Each case must be evaluated carefully with respect to the animal species involved, the environment in which the host is found and the mycobacterial species, and operational decisions made accordingly.