A 2-year-old boy was scheduled for patch closures of ASD and VSD. After anesthesia induction, infection of a double lumen central venous catheter (5 Fr, Arrow) was tried into the superior vena cava through the right jugular vein by Seldinger's method. We confirmed the placement of the catheter by drawing a small amount of blood. After the operation, chest X-ray examination in ICU revealed the misplacement of the catheter into his right intrapleural space. The catheter was left overnight to be used as a drainage route of a possible bleeding. Next morning, no abnormal finding in his chest X-ray and stable circulatory and respiratory conditions were found and we proceeded to extubate his endotracheal tube and take away the catheter. Two hours after the removal of the catheter, the boy showed forced respiration. He became cyanotic rapidly and then he needed emergency intubation. Following chest X-ray examination and an aspiration of intrapleural space revealed a severe hemothorax of the right side, where catheter had been inserted. The boy recovered without any disorders. This case suggests the importance to confirm the placement of CVP catheter, and to prevent the possible complications due to the malpositioned catheter.