We examined the effects of human immunodeficiency virus (HIV) infection and chronic alcohol consumption on cerebral phosphorus metabolites to determine if chronic alcohol abuse is a risk factor for the progression of neurological effects of HIV infection. We studied 15 HIV- alcoholics, 8 HIV- light/nondrinkers, 32 HIV+ alcoholics, and 41 HIV+ light/nondrinking men, with both HIV+ groups having similar CD4 lymphocyte counts. We used localized 31-phosphorus magnetic resonance spectroscopy after magnetic resonance imaging to examine two brain volumes in superior white matter and subcortical gray matter. Chronic alcohol consumption was associated with reduced white matter concentrations of phosphodiester (PDE) and phosphocreatine (PCr). Also in the white matter, acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC) were associated with reduced concentrations of PDE and PCr, compared with both HIV- and clinically asymptomatic HIV+ subjects. Because no alcohol-by-HIV interactions were detected, the effects of HIV infection and alcohol abuse were cumulative. This is reflected in a successive decrease of white matter PDE and PCr concentrations in the order HIV- light/nondrinkers/HIV- alcoholics/HIV+ light/nondrinkers/HIV+ alcoholics. Subcortical gray matter PDE concentrations were lower in ARC/AIDS alcoholics than in HIV- light/nondrinking individuals. These findings suggest altered brain phospholipid metabolites and energy metabolites with alcohol abuse and HIV infection. They demonstrate that the adverse metabolic effects of HIV on the brain are augmented by chronic alcohol abuse.