A 57-year-old female patient initially admitted with acute pancreatitis became extremely hypotensive, with increased central venous pressure, a few hours after insertion of a central venous catheter into the right subclavian vein. Echocardiography revealed a large amount of pericardial fluid, which was removed by pericardiocentesis. A cardiac tamponade as a result of central venous cannulation is a rare but serious complication with a high mortality rate. The tamponade may be the result of perforation of the V. cava superior, the right atrium or the right ventricle (as in the patient described). Cardiac tamponade should be suspected in any patient with severe hemodynamic problems after insertion of a central venous line.