Case MaterialWe identified five patients at the Hospital for Sick Children in Toronto with the horseshoe lung anomaly and reviewed their chest radiographs, angiographic studies in four patients, and pathologic material in four patients, including a postmortem bronchogram in one patient.The diagnosis of horseshoe lung anomaly was made from pulmonary angiography in four patients and confirmed at autopsy in three of these, from pulmonary angiography alone in one patient, and from autopsy findings alone in one patient. Four of the five patients became symptomatic in the neonatal period. One of these had complex congenital heart disease with hypoplastic left heart syndrome, severe coarctation of the descending aorta, and double-outlet right ventricle and died in the neonatal period. The four other patients had features of scimitar syndrome. Three of these presented in early infancy with respiratory distress, believed to be at least partly secondary to congestive heart failure, and died in the first few months of life. The fifth patient, who also had features of the scimitar spectrum, was asymptomatic and was investigated angiographically after a chest radiograph showed dextrocardia, small right lung, and abnormal pulmonary vascular markings. She has subsequently remained asymptomatic.Seven additional patients with horseshoe lung anomaly have been reported in the world literature [1-6].