To identify pathogens causing nosocomial fungal infections and the secular trend in their incidence in US hospitals, data from the National Nosocomial Infections Surveillance System, 1980-1990, were analyzed. During that period, 30,477 fungal infections were reported. The rate rose from 2.0 to 3.8 infections/1000 discharges. The highest number of nosocomial fungal infections/1000 discharges was reported from the burn/trauma service (16.1). Candida albicans was the most frequently isolated fungal pathogen (59.7%), followed by other Candida species (18.6%). The rate increased at all four major anatomic sites of infection. Patients with bloodstream infections who had a central intravascular catheter were more likely to have a fungal pathogen isolated than were other patients with bloodstream infection (relative risk = 3.2; P < .001): 29% of fungemia patients and 17% of patients with bloodstream infection due to other pathogens died during hospitalization (P < .001). Fungi are emerging as important nosocomial pathogens and control efforts should target fungal infections, especially fungemia.