Background and Aim: Although the retroaortic left brachiocephalic vein in isolation is of no clinical importance, its recognition in the setting of associated lesions is important. We sought to address issues concerning the influence of isomerism, the establishment of diagnosis, and its importance in various surgical and interventional procedures., Methods: A total of 80 published clinical and necropsy studies in the setting of a retroaortic left brachiocephalic vein described 250 patients. Clinical presentation, radiographic, ultrasonographic findings, contrast echocardiography, computed-tomographic angiocardiography, magnetic resonance imaging, and angiocardiography provided the diagnostic information prior to considering the surgical approach to the associated cardiac anomalies., Results: Among 250 reported cases, three-quarters had associated congenitally malformed hearts. Of these 189 patients, all but seven had usual atrial arrangement. Right isomerism was reported in five patients and two patients having left isomerism. Almost two-thirds had tetralogy of Fallot or its variants, over four-fifths had malformations involving the outflow tract, two-thirds had a right aortic arch with two patients having a cervical aortic arch, and onepatient had double aortic arch. Various innovative individualized surgical procedures were employed with an overall perioperative mortality of 3.4%., Conclusions: Although the retroaortic left brachiocephalic vein is asymptomatic, its recognition during clinical investigation should raise the possibility of an association with other malformations, especially right aortic arch, ventricular septal defect, and anomalies of the outflow tracts. We submit that an increased appreciation of this venous anomaly may facilitate surgical planning, endovascular procedures, placement of central venous lines, and transvenous pacemakers., (© 2021 Wiley Periodicals LLC.)