In many clinical settings, patients undergoing major surgery and patients with critical illness or cancer routinely receive a central venous catheter (CVC). Although several complications including hematoma formation, hemothorax, hydrothorax, chylothorax and cardiac tamponade with vascular injury are associated with the placement of CVCs, their incidence are not frequent. Especially, hydromediastinum and bilateral hydrothorax are very rare. We experienced an unusual complication of hydromediastinum and bilateral hydrothorax by left brachiocephalic vein perforation with misplacement of the catheter tip after right subclavian vein catheterization.