The purpose of this study was to determine if Mycobacterium leprae is an opportunistic pathogen in immunosuppressed subjects with HIV infection. Ninety six leprosy patients at Infectious Diseases Hospital (IDH), Nairobi were screened for, HIV-1 antibody between January 1991 and June 1992. The patients included 15 who were diagnosed during the study period and 81 who were previously diagnosed and were on anti-leprosy treatment. Blood was screened for HIV antibody by first ELISA and double positive samples were confirmed by a second ELISA. The HIV seronegative patients were re-tested serologically every 3 months. Smears from skin slits were used to determine bacterial index and the patients were classified according to criteria described by Ridley and Jopling. The patients were re-assessed clinically monthly. The mean age of the patients was 40 years and ranged from 13 to 78 years. Forty seven percent had paucibacillary and 53% had multibacillary leprosy. The HIV seroprevalence was 8% in previously diagnosed patients and zero in the newly diagnosed patients. There were no changes in clinical spectrum in HIV seropositive patients during follow up period; neither reversal reactions nor erythema nodosum leprosum were observed. The study suggests that M. leprae may not be an opportunistic pathogen in immunosuppressed subjects with HIV infection.