Chylothorax is a rare but generally severe complication of surgery of congenital heart disease. The authors report the clinical history of a young boy with complex congenital heart disease operated on several occasions and who developed severe and recurrent unilateral chylothorac after a bicavo-bipulmonary derivation. Conservative treatment followed by continuous somatostatin infusion was ineffective. Diagnostic Lipiodol lymphography was required before the chylothorax was cured. The authors describe management of this difficult case and discuss the therapeutic possibilities with reference to a brief review of the literature.