We report a fatal case of invasive pulmonary aspergillosis in a severely ill neonate and review 43 additional cases of invasive aspergillosis reported from 1955 through 1996 that occurred during the first 3 months of life. Eleven of the 44 patients had primary cutaneous aspergillosis, 10 had invasive pulmonary aspergillosis, and 14 had disseminated disease. Most infections were nosocomial in origin. Prematurity (43%); proven chronic granulomatous disease (14%); and a complex of diarrhea, dehydration, malnutrition, and invasive bacterial infections (23%) accounted for the majority of underlying conditions. At least 41% of the patients had received corticosteroid therapy before diagnosis, but only one patient had been neutropenic. Among patients who received medical and/or surgical treatment, outcome was relatively favorable, with an overall survival rate of 73%. Invasive aspergillosis may occur in neonates and young infants and warrants consideration under certain circumstances. Current therapeutic approaches consist of high-dose amphotericin B and appropriate surgical interventions.