The authors reviewed the medical histories and radiological examinations of five pediatric patients with a histologic diagnosis of Wegener's granulomatosis (WG) seen over a six year period in whom a total of 22 thoracic CT scans were performed. Involvement of both the upper and lower respiratory tracts was seen in all patients at presentation. One patient had subglottic stenosis necessitating tracheotomy. Pulmonary hemorrhage occurred in three patients at initial diagnosis. Classic cavitary lung nodules were seen in two patients--one at initial presentation, the other at relapse. The plain radiographic lower respiratory tract manifestations of pediatric WG were protean both at initial presentation and during follow up. Similarly, disease expression was highly variable on thoracic CT examinations but, overall, multifocal parenchymal infiltrates with or without small peripheral nodules were the commonest thoracic CT manifestations. As a consequence of cytotoxic and corticosteroid therapy the long-term prognosis of WG has improved considerably in recent years. Knowledge of the varied patterns of the primary disease and potential for iatrogenic complications are necessary for successful radiologic assessment of pediatric patients with WG.