Over a 51/2-year period, 22 of 262 children receiving liver transplants developed adenoviral infections. Five had adenoviral hepatitis in the allograft, caused by serotype 5. All five were treated for rejection, either just before or at the time of infection. Liver biopsy specimens had characteristic histological appearance, and diagnosis of adenoviral infection was confirmed with monoclonal antiadenoviral antibodies, electron microscopy, and by culture of liver tissue. In the remaining 17 patients, adenovirus was isolated from urine, stool, throat secretions, and/or blood samples, but none had any detectable visceral infection. Serotypes 1 and 2 predominated, similar to children not receiving transplants during the same time period. Three of the patients with hepatitis are alive and well; two died of liver failure. Adenoviral hepatitis did not recur in the second allograft of a patient who underwent retransplantation for combined rejection and adenoviral hepatitis, and appears, therefore, not to be a contraindication to retransplantation when liver failure ensues.