Spontaneous pneumothorax is a relatively frequent complication of human immunodeficiency virus (HIV) infection. Seven hundred sixty-five HIV-infected inpatients were treated at Marques de Valdecilla University Hospital between 1990 and 1996. Spontaneous pneumothorax developed in 9 patients. Pneumocystis carinii pneumonia was diagnosed in 6 patients (66%), either before or simultaneous to the appearance of pneumothorax. Pneumothorax was related to active or old tuberculosis infection in 3 patients (33%). Prophylactic therapy with nebulized pentamidine was used in 55% of the patients. Successful initial control of pneumothorax was achieved with simple drains in 58% of the episodes, although the recurrence rate was 71%. Pleurodesis with talcum with a chest tube was used successfully in 3 patients, in 2 because of sings of persistent air leakage uncorrected by simple drainage. Pleurodesis initially failed but later controlled pneumothorax the second time it was used. The mortality rate in this series was 66%, with a mean survival time of 55.6 days. We conclude that spontaneous pneumothorax is associated with poor prognosis in HIV infected patients. Prior or concurrent P. carinni pneumonia or tuberculosis were the etiologic factors identified in our patients. A simple pleural drain was associated with a high rate of recurrence, such that pleurodesis seems warranted in all patients.