Tuberculosis (TB) causes unnecessary deaths because of failure to diagnose and treat what is today a curable disease. A retrospective study was carried out in a general hospital to assess the magnitude of undiagnosed tuberculosis in hospitalized patients. Sixty-three cases of active tuberculosis, 39 of which were diagnosed only at autopsy, were found among 1306 autopsy cases during a three year study period. The reasons for the failure of diagnosis are discussed. For a correct diagnosis, the post-mortem examination must be systematic and include bacteriological and histological studies.