BACKGROUND Cardiac tamponade due to an intrapericardial infusion is a serious complication of central venous catheterization. METHODS An infant born at 35 weeks of gestation age, weighing 2300 g, was operated on at H10 for a duodenal stenosis. On day 2, a polyurethane central venous catheter was inserted for parenteral nutrition via his right internal jugular vein. A frank blood return was obtained and a chest X-ray taken 2 hours later showed that the tip into the catheter was in the right ventricle. Four hours after insertion, a sudden deterioration of the infant's status led to tracheal intubation and artificial ventilation on 100% oxygen; no improvement was noted. The heart rate was 135 bpm, but the differential blood pressure was decreased at 68/56 mmHg and there was no blood return on the catheter. Cardiac tamponade was then suspected and immediately confirmed by pericardial tap that yielded 10.5 mL of the infused solution. The catheter tip was then repositioned and a good blood return was obtained. The infant's breathing and hemodynamic status improved dramatically. CONCLUSIONS The use of very thin and flexible central venous catheters does not eliminate the risk of perforation of the cardiac chambers. A cardiac tamponade must always be considered in children with a central venous catheter when a sudden deterioration of hemodynamic status is noted.