We report a case of a 29-year-old male patient with a generalized adenovirus (AdV) infection after cord blood transplantation (CBT) for acute myelocytic leukemia with maturation at 2nd complete remission. Before engraftment, hemorrhagic cystitis was caused by AdV, which resulted in hydronephrosis, renal failure, and adenoviremia on day 34. Forced diuresis, hemodialysis, withdrawal of cyclosporin A, and administration of gamma-globulin or vidarabine were not effective and the patient died of pulmonary alveolar hemorrhage on day 67. At autopsy, old inflammatory change only was observed in the bladder section. In the lungs and kidneys, granular deposits in the nucleus and a high copy number of AdV-DNA were observed. Molecular diagnosis using PCR-restriction fragment length polymorphism analysis demonstrated that AdV with the serotype 14 caused the cystitis. However, retrospective genome typing using PCR sequencing revealed the infection of AdV serotype 35 in the kidneys, lungs, and serum. The present case suggested that Adv infection could not be always caused by a single AdV serotype, and suggested that multiple serotype infection was very difficult to treat. It is desired that a consensus regarding the treatment of AdV infections is established.