Chylothorax is the accumulation of lymphatic fluid in pleural space following traumatic injury to lymphatic vessels, systemic venous obstruction, dysfunction of the right ventricle, thrombosis of the duct, superior vena cava or subclavian vein, or postoperatively. A 2 ½-year-old male child operated for transposition of great arteries (TGA), tricuspid atresia (TA), and hypoplastic right ventricle 15 days ago developed chylothorax and left internal jugular vein thrombus. The child was initially managed conservatively with nutritional management, anticoagulation, and octreotide followed by interventional radiological management with lipoidol injection. Early suspicion and diagnosis are crucial. The management was difficult owing to a lack of proper guidelines. Further research is warranted.