To define the extent and nature of mycobacterial infection in patients on an adult dialysis unit whose catchment population contains a large proportion of non-Caucasian subjects, a retrospective survey of all new patients accepted onto our maintenance dialysis programme between January 1987 and December 1989 was carried out. Twenty-six Asian, 13 Afro-Caribbean, two Oriental and 170 Caucasian patients were accepted onto the dialysis programme in the three-year recruitment period. Eight of the 26 Asian patients, but none of the others, had developed mycobacterial infection by the end of December 1990. One patient had a cerebral tuberculoma with miliary mottling on chest X-ray, one pulmonary tuberculosis, one tuberculous adenitis and 5 tuberculous peritonitis (four due to Mycobacterium tuberculosis and one Mycobacterium kansasii). All the patients had been living in the UK for an average of 15 (range 6-24) years, with no known recent exposure to tuberculosis. Five patients are now alive and well, one developed malabsorption following M. kansasii peritonitis, but two with tuberculous peritonitis died before treatment could be instituted. Mycobacterial infections were associated with a high level of mortality and morbidity. No Asian patient developed mycobacterial infection during post-transplant immunosuppressive therapy in the study period, probably because of the routine anti-tuberculous chemoprophylaxis employed in this group of patients. The diagnosis of mycobacterial infection should be suspected when an Asian dialysis patient develops a pyrexia of unknown origin. It is likely, though not proven, that anti-tuberculous chemoprophylaxis might reduce this high incidence of tuberculous infection in Asian dialysis patients.