We analysed 2200 echocardiographies performed during last 18 months.Out of 1970 abnormal echocardiographies, 10 patients were found to have retroaortic innominate vein(0.55%). It was diagnosed using suprasternal short axis view. Out of these 10 patients, 8 were diagnosed to have tetralogy of Fallot(TOF) and two had univentricular heart with severe pulmonary stenosis. It was not seen in normal echocardiograms. out of these 10 patients, seven patients had right aortic arch and two had pulmonary atresia. There was a high incidence of retroaortic innominate vein in patients with TOF. We had 108 patients with TOF out of which 8 had its presence (8.5%). In 8 patients its presence was confirmed during surgery. No other imaging modality was used for confirmation. Though its presence in isolation has no clinical significance, its presence needs to screened carefully especially in patients with right ventricular outflow tract obstructions and right aortic arch. It can be mistaken for left superior vena cava or right pulmonary artery. If undiagnose, its presence may cause technical difficulty during pacemaker insertion, superior vana caval cannulation during surgery and exposure of pulmonary artery during Glenn anstomosis. Its presence has a embyological significane.Reduced shortening of aortic arch as seen in right aortic arch, compresses and prevents development of superior transverse venous plexus. Abnormal development of pulmonary arteries in pulmonary stenosis or pulmonary atresia encourages sparing of inferior transverse venous plexus leading to formation of anomalos retroaortic course of innominate vein.