The authors analyzed the use of hospitals by patients with a diagnosis of human immunodeficiency virus (HIV) infection, using data from the National Hospital Discharge Survey. In the period 1984-90, the rates of both discharges and days of care for HIV-infected patients rose dramatically. For 1988-90, black males had the highest HIV-related discharge rate, followed by white males and black females, whose rates were similar. The discharge rate for patients with HIV-related diagnoses increased more in the Northeast than in the three other regions of the country. By 1990 the rate for the Northeast was nearly triple the rate for other major regions. More than half of female and black patients with HIV-related diagnoses were hospitalized in the Northeast. Private insurance was the principal expected source of payment for the care of half of the HIV-infected patients discharged in 1985, but for only a third in 1990. Medicaid covered 40 percent of the patients with HIV-related diagnoses discharged in 1990. Larger proportions of female than male patients and of black patients than white patients were covered by Medicaid. Acquired immunodeficiency syndrome was the diagnosis coded for most patients with an HIV-related diagnosis, but in larger proportions for patients who were male or white patients. Nonspecific HIV diagnoses were coded for larger proportions of female and black patients. HIV-infected patients had an average of 3.6 diagnoses in addition to their HIV diagnosis. Nearly a fourth of the additional diagnoses were for other infectious diseases, such as pneumocystosis or candidiasis. Anemia, pneumonia, and drug use and dependence also were frequent diagnoses.