Close to 3 years into widespread PI use, several toxicities, including metabolic alterations, are being reported increasingly in conjunction with the use of PI-containing regimens. Some of the manifestations of these metabolic alterations include hyper/dyslipidemia, hyperglycemia, insulin resistance and glucose intolerance, lipodystrophy (in face and extremities), and body fat redistribution (e.g., central obesity and buffalo humps). Despite reports of increasing prevalence of metabolic complications among PI users, the question of whether they result from PI therapy has not been answered. Some of these complications, e.g., a decrease in peripheral fat with an increase in visceral fat and buffalo hump, have been observed in HIV-infected individuals who were not receiving PIs. This study compares 3 different antiretroviral regimens used in the FIRST study (CPCRA 058), 1 of which does not contain a PI, and examines metabolic alterations which occur.