Remarkable and dramatic strides have been made over the last 4 years in the management of human immunodeficiency virus (HIV) infection. Better education of the virology of HIV has provided the opportunity to target therapies for the virus. Currently, HIV-infected patients are treated with combinations of potent antiretroviral agents that usually include a protease inhibitor, termed highly active antiretroviral therapy (HAART). With these drug regimens, HIV replication can be profoundly suppressed, and in some patients, circulating virus becomes undetectable. Even in the patient with advanced disease, the CD4 lymphocyte count will rise, reflecting a redistribution of CD4 cells. The clinical correlation is that the risk for opportunistic processes becomes reduced, and conversely, overall survival is improved. The long-term prognosis for these patients still remains dictated by the severity of immunodeficiency (absolute number of CD4 cells) and the level of circulating virus.