To determine if the use of corticosteroids for presumed Pneumocystis carinii pneumonia exacerbated undiagnosed tuberculosis or increased the likelihood of reactivation tuberculosis, we reviewed medical records of 144 hospitalized HIV-infected patients who received antipneumocystis therapy. Ninety-four patients (Group C) received corticosteroids and 50 patients (Group NC) did not. One hundred and thirty-seven patients (97%) had acid-fast stains and mycobacterial cultures performed. Group C and Group NC were similar in ethnicity, distribution of HIV risk factors and CD4 cell count. Eight (9%) Group C patients and seven (14%) Group NC patients had culture-proven tuberculosis during their hospitalization. After a median followup of 16 mo after discharge, one (2%) Group C patient and two (4%) Group NC patients developed tuberculosis. Only one patient in Group C died of tuberculosis, despite receiving antituberculosis therapy. We conclude that the use of corticosteroids for presumed P. carinii pneumonia does not increase morbidity from undiagnosed tuberculosis or increase the frequency of reactivation tuberculosis.