In hypoplastic left heart syndrome (HLHS) mitral and aortic valves are atretic or critically stenotic with hypoplasia of left atrium (LA), left ventricle (LV) and ascending aorta. It is a duct dependant lesion. Systemic flow depends upon patency of ductus arteriosus. Coronary arteries are filled by retrograde flow from ductus through the hypoplastic ascending aorta. Ventriculo-coronary flow also occurs through myocardial sinusoids. In HLHS the neonates are born healthy with no cyanosis, no murmur, with little scope to diagnose such a deadly disease. But after some hours to a day or two the infant becomes critically ill and may die due to closure of ductus. Cyanosis, irritability, low volume pulse with hypotension, RV impulse, single second heart sound and no murmur or short systolic murmur are main clinical features. ECG shows right axis, right atrial enlargement and right ventricular hypertrophy with no q and small r in V5 and V6 indicating no LV force. Chest X-ray shows cardiomegaly with absent ascending aortic shadow (reverse of ‘5’ appearance). Echocardiography findings are atretic or stenotic mitral and aortic valves, thick walled small left ventricle, small left atrium and hypoplastic ascending aorta. This anomaly can be diagnosed in prenatal period by fetal echocardiography. Cardiac catheterization and angiography are mandatory before any surgical procedures. Reconstructive surgery is done in staged manner.