Summary Tuberculosis and other mycobacterial infections continue to pose a major world-wide threat to human health, especially in association with the HIV epidemic. Increased awareness of mycobacterial infection leads to increased demands on microbiology laboratories. Although direct microscopy of stained smears and culture on egg-containing media remain the cornerstones of laboratory diagnosis of mycobacterial infections, new approaches such as radiometry, chromatography and nucleic acid technology are radically changing the practice of 'conventional' mycobacteriology. Already isolation, identification and sensitivity testing have been speeded up by these new techniques and further improvements are likely. Nucleic acid technology will allow fingerprinting of individual strains and detailed studies of the epidemiology of mycobacterial infections. In spite of new methodology and new approaches, culture and sensitivity testing will continue to be necessary both for the management of individual patients and to provide information on the spread of drug resistance.