Cardiac tamponade following central line in a neonate is rare and an uncommon situation; however, it is potentially reversible when it is diagnosed in time. We report a case of cardiac tamponade following central line insertion. A 10-day-old 2.2 kg girl operated for obstructed total anomalous pulmonary venous connections had neckline slipped out during extubation. Attempted cannulations of right femoral vein were unsuccessful. At the end of the left internal jugular vein cannulaton, there was a sudden cardiorespiratory arrest. Immediate transthoracic echocardiogram showed left pleural and pericardial collection. Chest was opened and the catheter tip was seen in the thoracic cavity after puncturing the innominate vein. The catheter was removed and the vent was repaired.