Bacterial infections, including those that cause infection in the healthy host as well as those that are more opportunistic, occur very commonly among persons infected with the human immunodeficiency virus (HIV). Bacterial infections are a direct result of the severe humoral and cellular immune defects found in these patients. Epidemiologic factors such as intravenous drug use and stage of HIV infection may also play important roles. Pulmonary, bloodstream, gastrointestinal, central nervous system, skin and soft tissue, and catheter鈥恟elated infections are common, as are endocarditis, prostatitis, and others. Frequently reported pathogens are common organisms such as Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumoniae, and enteric gram鈥恘egative pathogens, as well as less typical ones such as Listeria monocytogenes and Nocardia sp. The frequency of infection is specific to organ system and pathogen, often being many times higher than in immunocompetent hosts. Prompt recognition and aggressive therapy are required to reduce morbidity and mortality due to these infections.