PURPOSE: To describe the radiologic features of lower respiratory infections associated with adenovirus inchildren and to determine whether these can be differentiated from other lower respiratory infections. MATERIALS AND METHODS: We retrospectively reviewed the radiologic features of 48 lower respiratory tract infectionsassociated with adenovirus in children and diagnosed between December 1990 and August 1996 at Seoul NationalUniversity Children's Hospital. Adenovirus was identified by either viral culture or immunofluorescent staining ofnasal aspirates and/or pleural fluid, and serotested by microneutralization. They were divided into three groups,as follows: type 7 epidemic infection (group I); type 3 sporadic infection (group II); and other(types 1, 2, 4,5, 6) sporadic infection (group III). Each radiological finding was tested for differences among three groups withFisher's exact test. RESULTS: The major radiologic features of adenoviral lower respiratory infection(n=48) werebilateral parahilar peribronchial infiltration(90%), hyperaeration(73%), consolidation(58%), atelectasis(56%) andpleural effusion (31%). In group I(n=27), II(n=8), and III(n=13), bilateral parahilar peribronchialinfiltration(93%, 88%, 85%, respectively), hyperaeration(63%, 88%, 85%), atelectasis(52%, 38%, 77%), pulmonaryconsolidation(81%, 63%, 8%) and pleural effusion(44%, 38%, 0%) were seen. In groups I and II, pulmonaryconsolidation was multiple(82%, 80%, respectively), bilateral(55%, 60%), or extensive(36%, 40%). The prevalence ofconsolidation and pleural effusion in groups Iand II was significantly higher than in group III(p < .05). CONCLUSION: Pulmonary consolidation and pleural effusion, regarded as characteristics of bacterial pneumonia,were common findings in types 7 and 3 adenovirus infections. Parahilar peribronchial infiltration, hyperaeration,and bilateral, multiple, extensive consolidation may be features which can determine whether an infection isadenoviral or due to bacterial pneumonia.