The study demonstrates that delirium in acquired immune deficiency syndrome (AIDS) patients is associated with mortality, the need for long-term care, and an increased length of hospitalization. Data were collected prospectively on human immunodeficiency virus (HIV)/AIDS patients admitted to a teaching hospital from January 1996 through December 1996. The data included demographic characteristics of the participants, medical diagnoses, CD4 cell count, Karnofsky functional assessment, mortality during admission, length of stay, and discharge placement. Participants were evaluated throughout their hospital stay for evidence of delirium. The presence of delirium was determined using DSM-IV diagnostic criteria. There were no significant differences between delirious and nondelirious patients with respect to demographic characteristics or markers of medical morbidity. Patients with delirium were more likely to die during admission (chi-square [chi2] = 39.1, df = 1, P<.0010), to stay longer in hospital (t = 3.50, df = 12.9, P<.0041), or to need long-term care if discharged alive (chi2 = 12.8, df = 2, P<.0021). Delirium is associated with adverse outcomes in hospitalized AIDS patients. More research is needed to characterize the nature of this association.