Congenital, idiopathic, pathological and iatrogenic chylothorax is encountered across all age groups. The aetiology and pathogenesis of the congenital chylothorax is unknown. Some congenital malformations and pathologies are known to be associated with chylothorax. Congenital diaphragmatic hernia after its correction can present with chylothorax as persisting and challenging problem. Thoracic chylous lymphatics can be accidentally injured during surgery or can leak after a blockage from an obstructing tumour or venous thrombosis of superior vena cava. Specific investigations to identify its causative aetiology are indicated in adult chylothorax. In infants and children, imaging is carried out after initial supportive measures have failed to resolve chylothorax. Respiratory compromise as a result of pleural collection of chyle may require drainage and ventilatory support. Chyle production can be reduced by withholding enteral nutrition and providing total parenteral nutrition. Surgical approach is considered in prolonged and intractable cases. Outcome can be variable depending on its aetiology, associated genetic and congenital malformations.