AbstractThis paper describes the clinical and radiological findings in three infants with agenesis of a single lung. In the two cases of right lung agenesis, severe gastro-oesophageal reflux was present. In these two cases, contrast-medium-enhanced computed tomography (CT) excluded vascular compression of major airways in one patient but demonstrated mild compression in the other. Conventional CT in the case of left lung agenesis demonstrated posterior herniation of the contralateral right lung.