Eight patients with isolation of a subclavian artery are described. Isolation of subclavian artery is defined as a loss of continuity between the subclavian artery and aorta but with persistent connection to the homolateral pulmonary artery through a ductus arteriosus. The connecting ductus arteriosus may or may not be patent. As the pulmonary vascular resistance is usually lower than the systemic resistance, the isolated subclavian artery is perfused by subclavian steal, and if the connecting ductus arteriosus is patent, flow occurs from the subclavian artery into the pulmonary artery. In this material and in all reported cases, isolation of subclavian artery has always been associated with other anomalies of the aortic arch, such as right aortic arch or bilateral ductus. Its frequent association with intracardiac defects, usually the tetralogy of Fallot, makes its recognition clinically important. Thoracic aortography with delayed filming is the only procedure that allows consistent diagnosis of this rare anomaly during life.