PIP: Infection with Mycobacterium tuberculosis is so common in tropical areas that the World Health Organization (WHO) estimates more than 75% of the 8-10 million new cases of tuberculosis (TB) annually occur therein. Infection with HIV is also common in the tropics; the WHO estimated in 1992 that 9-11 million adults were infected with HIV, mostly in developing countries. This tropical overlap of HIV infection and pulmonary pathogens makes pulmonary infections a common manifestation of HIV infection, especially TB and bacterial pneumonia. Bacterial pneumonia accounts for at least 25% of medical admissions to one of East Africa's largest hospitals and recent cohort and case-control studies have shown increased rates of disease among HIV-infected individuals. Of all the pulmonary infections encountered in the tropics, however, M. tuberculosis is one of the most significant pathogens. Data from sub-Saharan Africa and Haiti have shown that 17-66% of TB cases are seropositive for HIV-1. Moreover, 50% of seropositive patients presenting with pulmonary symptoms have TB. This review, however, focuses upon non-tuberculosis pathogens affecting HIV-infected patients in tropical and developing countries. Pneumococcus, nocardiosis, and melioidosis are discussed under bacterial pneumonia and are followed by cryptococcosis, histoplasmosis, paracoccidioidomycosis, and penicillium marneffei under fungal pneumonia. Other sections explore pneumocystis pneumonia, parasitic pneumonia (strongyloidiasis), pleural effusions, and the evaluation of HIV-infected patients with pulmonary disease.