This article reviews the importance of preventing illness in HIV-infec
ted patients. The indications and medication regimens for preventing s
everal common opportunistic complications are discussed. Infections ad
dressed include pneumocystis pneumonia, Mycobacterium avium complex, t
oxoplasmosis encephalitis, and tuberculosis, among others. Other preve
ntive interventions such as routine immunizations are addressed briefl
y as well. Diagnosis and treatment of five of the most common HIV-asso
ciated opportunistic infections are reviewed.