The aim of this study was to determine the contribution of injected-drug-use complications to the utilization of inpatient care by persons infected with human immunodeficiency virus (HIV). Retrospective chart review was done of all hospital admissions between January 1, 1991, and December 31, 1991, with outpatient records reviewed to establish CD4 counts within 3 months of the date of admission. The participants included 284 consecutive admissions (189 patients); admissions were divided into two groups according to the Center for Disease Control 1993 expanded AIDS definition: those with AIDS (CD4 count, <200 cells/μl) and those with early HIV disease (CD4 count, >200 cells/μl). Thirty percent of admissions occurred among persons with early HIV disease. Among 189 individuals admitted to the hospital, 84% were male, 62% were white, and 48% had injected drugs. Early HIV disease admissions were more likely to involve active injection-drug users (82% vs. 33%;p< 0.01). Admissions related to injected-drug use constituted 60% of early HIV disease hospitalizations, and this number rises to 72% if bacterial pneumonia is included as a substance abuse complication. Admissions related to injected-drug use constituted 27% of AIDS admissions: this number rises to 51% if bacterial pneumonia is included. Early HIV disease admissions were significantly shorter (9.9 vs. 12.6 days) and less expensive (mean charge, $9,592 vs. 12.873) than AIDS admissions but still accounted for 25% of inpatient HIV charges. Hospitalizations among HIV-infected persons early in the course of HIV disease are most often related to the medical complications of injected-drug use and account for a substantial expenditure of hospital resources. Early outpatient HIV care should focus not only on slowing the progression of HIV disease but also on limiting the morbidity of injected-drug use.