Abstract: Chylopericardium is a rare clinical entity in which chylous fluid accumulates in the pericardial cavity. We report a case of recurrent massive idiopathic chylopericardium with tamponade in a 3-year-old infant with no history of trauma, thoracic surgery, malignancy, infection or tuberculosis. Echocardiography showed a large amount of pericardial effusions with evidence of tamponade. And 450 mL of fluid was evacuated by pericardiocentesis. She successfully responded to 30 days of continuous pericardial drainage and 15 days of a medium-chain triglyceride diet. We conclude that if a patient is asymptomatic and can well tolerate daily life, surgery including surgical ligation of the thoracic duct and creation of a pericardial window is not necessarily required.