Tuberculosis (TB) is a significant disease for both humans and animals. Susceptibility to Mycobacterium tuberculosis is relatively high in humans, other primates and guinea pigs. Cattle, rabbits and cats are susceptible to M. bovis and are quite resistant to M. tuberculosis. Wild hoofed stock is generally susceptible to M. bovis, but few reports are available on the isolation of M. tuberculosis. Swine and dogs are susceptible to both M. bovis and M. tuberculosis. M. bovis accounts for only a small percentage of the reported cases of TB in humans; however, it is a pathogen of significant economic importance in wild and domestic animals around the globe, especially in countries where little information is available on the incidence of M. bovis infection in humans. Unlike transmission of M. bovis from cattle to humans, the role of human-to-human airborne transmission in the spread of M. bovis has been somewhat controversial. Investigations are needed to elucidate the relative importance of M. bovis on TB incidence in humans, especially in developing countries. Efforts should be concentrated in countries where human immunodeficiency virus (HIV) infection is widespread, as HIV-infected individuals are more susceptible to mycobacterial disease. Eradication of M. bovis in cattle and pasteurisation of dairy products are the cornerstones of the prevention of human disease.