Nosocomial infections appear to be increased in patients with acquired immunodeficiency syndrome (AIDS), compared to individuals with asymptomatic infection due to human immunodeficiency virus (HIV). Risk factors for bacterial colonization and infection include immunosuppression, prior treatment with some antibiotics, increased hospitalizations with longer lengths of stay, greater exposure to invasive devices such as indwelling intravenous or urinary catheters, and the degree of immunosuppression. Data suggest that other infectious agents such as Pneumocystis carinii, Mycobacterium tuberculosis, Mycobacterium avium complex, and Cryptosporidium may be acquired in healthcare facilities. Diagnosis and management of nosocomial infections in HIV-infected persons may be complicated by an atypical presentation, increased rates of relapse following treatment, presence of multiple infections, and early discharge from the inpatient setting. Accurate assessment of nosocomial infections and outbreaks in the hospital is complicated by limited data on the risk of transmission of both traditional and unusual pathogens in this population. Furthermore, some patients may acquire nosocomial pathogens during their initial hospitalization and present later with infections that normally would be classified as community acquired. Therefore, there probably is an underestimation of current nosocomial infection rates, and perhaps “hospital-associated” or “healthcare-facility–associated” might be more accurate terms for these infections (Infect Control Hosp Epidemiol 1996;17:304-318).