Pneumothorax occurs in 1 to 2% of hospitalized patients with HIV and is associated with 34% mortality. Pneumocystis carinii pneumonia and chest radiographic evidence of cysts, pneumatoceles, or bullae are risk factors for spontaneous pneumothorax. Tube thoracostomy, pleurodesis, and surgical treatment are usually needed to manage spontaneous pneumothorax in AIDS. Pleural effusion is seen in 7 to 27% of hospitalized patients with HIV infection. Its three leading causes are parapneumonic effusions, tuberculosis, and Kaposi sarcoma. Pleural effusions occur in 15 to 89% of cases of pulmonary Kaposi sarcoma and in 68% of cases of thoracic non-Hodgkin lymphoma in patients with AIDS. Primary effusion lymphoma accounts for 1 to 2% of non-Hodgkin lymphomas. Kaposi sarcoma and primary effusion lymphoma are associated with human herpesvirus 8. The prognosis of patients with pleural Kaposi sarcoma and non-Hodgkin lymphoma in AIDS is poor, and the major goal of treatment is palliation.