Although bronchiolitis obliterans (BO) is seen commonly after heart-lung transplantation, its occurrence after lung transplantation appears to be relatively infrequent. In the 55 single- and double-lung transplantations performed at Toronto General Hospital, 41 patients have survived longer than 3 months and four (10%) have developed pathologically proved BO. Chest radiographic findings in these four patients included slight to moderate decreased peripheral vascular markings (n = 3), slight to moderate volume loss (n = 2), subsegmental atelectasis (n = 2), and new, thin, linear, irregular areas of increased opacity (n = 2). High-resolution computed tomography (HRCT) demonstrated mild peripheral bronchiectasis (n = 4) and decreased peripheral vascular markings (n = 3). Although the radiographic and HRCT findings did not appear to be specific for posttransplantation BO, they may be of value in suggesting the diagnosis of BO within this patient population.