A total of 177 tuberculosis cases of individuals not infected with human immunodeficiency virus diagnosed during the years 1984-1990 at the Helsinki University Central Hospital were reviewed retrospectively to compare the clinical presentation of tuberculosis in patients immunocompromised because of treatment (n = 35) with patients with other underlying conditions (n = 60) and with those without known predisposing factors (n = 82). In immunosuppressed patients compared with other patients, tuberculosis was more frequently disseminated (40% vs. 12%, P < 0.001), lung infiltrations were more often miliary (44% vs. 13%, P < 0.001), and the sputum smears were less often positive (30% vs. 62%, P < 0.05). In addition, the age-adjusted odds ratio for the risk of dying was higher among immunosuppressed patients than among the two other groups. The low rate of positive sputum smears and the high rate of atypical presentation and mortality stress the importance of a high index of suspicion and early institution of empirical antituberculosis therapy in immunosuppressed patients.