Abstract. Umbilical venous catheters are commonly used for establishing central venous access during the first 10 days of life. Despite their routine use, they are frequently malpositioned and may occasionally be associated with serious complications. We report a rare case of an extremely low birthweight infant who developed severe and fatal pericardial effusion following umbilical venous catheterization. Chest radiography showed no cardiomegaly; bedside ultrasonography established the diagnosis and was used to guide pericardiocentesis.