Although noted early in the HIV epidemic, metabolic abnormalities came to prominence when potent combination antiretroviral therapy was introduced. Complications associated with HIV infection and antiretroviral therapy include cardiovascular disease, lipid disorders, glucose metabolism disorders, adipose tissue disorders, bone metabolism disorders, and lactic acidosis. Metabolic complications have driven the discovery of new agents and classes of antiretrovirals, and have shaped guidelines for the management of HIV infection. However, significant uncertainty remains about pathogenesis and management. Substantial complexity exists in the treatment of these disorders, illustrated by the complex drug-drug interactions between lipid-lowering agents and antiretroviral regimens. Several important new developments include the association of a higher risk of cardiovascular events with the discontinuation of antiretroviral therapy or use of specific drugs like abacavir and didanosine. This article reviews the current understanding of metabolic abnormalities associated with HIV and its treatment.