Ten cases of neonatal adenovirus infection are reported. These infants were admitted to the intensive care nursery or intermediate care nursery of a tertiary care hospital between January 2000 and March 2003. The birth history, clinical manifestations, treatment, and outcomes were retrospectively reviewed. The mean age at onset of illness was 5.7±8.52 d, and the male to female ratio was 2.33 (7/3). Of the 10 newborns, 4 were premature. Four of 10 patients were delivered by cesarean section, indicating that vaginal delivery is not the only route of transmission for perinatal adenovirus infection. Although 4 patients had disseminated disease, the rest had less-severe infections, with manifestations ranging from simple oral ulcers, to fever gastrointestinal tract symptoms (bloody stool, diarrhea, and hepatitis), hematologic abnormalities (thrombocytopenia and neutropenia), and neonatal seizures. None of the study patients died. In conclusion, neonatal adenovirus infection is not as rare, or as fatal as previously thought, and the severity of disease is variable. Neonatal adenovirus infection should be considered in the differential diagnosis of neonatal infection, particularly in the setting of negative cultures of bacteria or other common viruses.