Adenoviruses have recently been recognized as etiologic agents of enteric disease in hospitalized infants and young children. Patients who have undergone surgical procedures related to the complications of neonatal necrotizing enterocolitis constitute a population of infants who are often hospitalized for extended periods of time. We studied the incidence of enteric adenovirus infections in infants with necrotizing enterocolitis who had undergone intestinal surgery resulting in colostomies or ileostomies. These studies revealed that 31.7% of the hospital admissions in such patients were complicated by symptomatic infection with enteric adenoviruses. The rate of adenovirus infection in this population was significantly higher than the rate of such infections encountered in infants undergoing ostomy procedures for other conditions and in age-matched hospitalized infants without prior gastrointestinal surgery. The infections with enteric adenovirus were generally accompanied by an increase in intestinal output which was temporally associated with the excretion of adenovirus in the intestinal fluid. In addition infections with enteric adenoviruses in the infants with necrotizing enterocolitis and ostomies were associated with a marked increase in length of hospitalization as compared to uninfected infants with similar underlying gastrointestinal pathology. Epidemiologic analysis revealed that many of the cases of enteric adenovirus infection in the study population occurred during seasons in which enteric adenovirus infections were prevalent in the hospital population. These studies demonstrate that enteric adenovirus infections are major causes of morbidity in hospitalized patients who have of morbidity in hospitalized patients who have undergone ileostomy or colostomy procedures for necrotizing enterocolitis and that the prevention of enteric adenovirus infections might result in a significant improvement in the hospital care of infants with these conditions.