There is little information about nosocomial transmission of tuberculosis (TB) in sub-Saharan Africa. A study was carried out to examine the process of diagnosis and treatment of smear-positive pulmonaryTB patients in Queen Elizabeth Central Hospital, Blantyre, Malawi, and the incidence ofTB in nurses working in specific departments of the hospital. Case notes of 1365 patients with smear-positive pulmonary TB, diagnosed and treated at the hospital in 1993 and 1994, were analysed.The number of qualified nurses who worked in specific departments of the hospital between 1993 and 1994 and the number who were diagnosed and treated forTB during this period were obtained from nursing records. 787 patients (58%) were diagnosed as out-patients and 578 (42%) were diagnosed in hospital wards, 544 from medical wards. In medical wards, there were long delays from the time of admission to diagnosis and start of anti-TB treatment in new and previously treated TB patients. Of 310 qualified nurses, 12 (4%) were treated for TB in 1993-1994; 4 (14%) of 29 nurses working in the medical wards developedTB.The results indicate the importance of finding simple measures in resource-poor countries to improve the diagnosis and treatment ofTB in hospital patients in order to decrease the risk of nosocomialTB transmission.