Anomalous subaortic left brachiocephalic vein (ASLBV) is a rare systemic venous anomaly. We review our experience with patients associated with ASLBV who underwent cardiac surgery at three institutions. From 1989 to 2009, the medical records of surgically treated patients with ASLBV were analyzed; the incidence of ASLBV, clinical characteristics, and associated anatomical findings were assessed. Fifteen patients had ASLBV. All ASLBVs coursed left lateral to the aortic arch, passed under the ascending aorta anterior to the central pulmonary artery, and joined the right brachiocephalic vein. Fourteen patients had congenital heart disease (CHD), and the remaining patient did not have cardiac anomalies. Its incidence was 0.57% (14 of 2,449) in patients with CHD and only 0.02% (1 of 4,805) in patients without CHD. In patients with CHD, 73.3% (11 of 15) of the patients had conotruncal cardiac anomalies such as tetralogy of Fallot, ventricular septal defect with pulmonary atresia, truncus arteriosus, and interruption of the aortic arch. Eight patients had aortic arch anomalies, including right aortic arch and cervical aortic arch. The deletion of chromosomal 22q11.2 was confirmed in two patients, and one patient was diagnosed with DiGeorge syndrome. ASLBV was clinically silent even without any surgical intervention. ASLBV is a very rare anomaly and is highly associated with conotruncal cardiac anomalies and aortic arch anomalies, including right aortic arch and cervical aortic arch. Preoperative diagnosis is important when any surgical interventions are intended, especially, in patients with conotruncal cardiac anomalies. Clin. Anat. 23:950-955, 2010. (C) 2010 Wiley-Liss, Inc.