Sub-Saharan Africa, which has just over 10% of the world's population, is home to more than 25 million people living with HIV/AIDS-two thirds of the global total. Opportunistic pulmonary infections are major causes of morbidity and mortality among HIV-infected adults in the subcontinent. Of these diseases, tuberculosis (TB) is by far the most prevalent and serious, and in some countries it causes one third or more of all AIDS-related deaths. Because it is so frequent and a major public health problem, TB tops the list of differential diagnoses of people-with or without coexisting HIV infection-who present to the health care system with chronic cough and other pulmonary symptoms. As HIV-induced immunosuppression worsens, the clinical and radiographic manifestations of TB become increasingly atypical. Second among HIV/AIDS-associated pulmonary complications is community-acquired pneumonia, most commonly caused by Streptococcus pneumoniae, which usually responds to standard beta-lactam antimicrobial agents. The prevalence of Pneumocystis jirovecii pneumonia is increasing, due to both improved recognition of its characteristic clinical and radiographic features and aggressive diagnostic interventions. Treatment outcome in most countries, however, has been poor. Combined infections, usually including TB, are common. Pulmonary nocardiosis, cryptococcosis, Kaposi's sarcoma, and (possibly) histoplasmosis appear to be infrequent, but probably underdiagnosed. Improved diagnosis, treatment, and prevention of all these diseases are urgently needed, but a greatly expanded antiretroviral treatment program will help most of all.