The imaging studies obtained after single-lung transplantation in 14 patients were reviewed. The reimplantation response occurred in 13 patients and was an early, transient process, which varied in its manifestations from a subtle perihilar haze to dense consolidation with air bronchograms. Nine episodes of acute rejection, an imprecise clinical diagnosis, occurred in eight of the patients. The associated chest radiographic changes were variable and included basal or diffuse reticular interstitial disease in three cases and basal and/or perihilar consolidation in three cases; no change was detected in three cases. On four occasions, the radiographic changes resolved within 24 hours of intravenous corticosteroid administration. The radiographic findings associated with the reimplantation response and rejection were nonspecific and could have been mistaken for those of fluid overload, atelectasis, mucous plugging, and pneumonia. Bronchial dehiscence was well demonstrated by the finding at computed tomography of extraluminal air adjacent to the bronchial anastomosis. One patient developed multiple pulmonary nodules due to cyclosporine-induced lymphoma.