Cyanosis or bluish discoloration of toenail, fingernail and tongue is children is generally termed as blue baby syndrome. Most commonly it is associated with a complex congenital heart defect which causes mixing of oxygenated or impure blood with oxygenated or pure blood in the heart. The child may be blue from the birth or develops the disease after some time following birth. What ever the timing of presentation this bluish discoloration needs urgent medical attention. The most common disease in Indian population causing this symptom is Tetralogy of Fallott’s( TOF).TGA, DORV, Univentricular heart, TAPVC etc. are the complex congenital heart diseases that can produce similar symptoms.