We analyzed 385 consecutive central venous catheter (CVC) attempts over a 6-month period. All critically ill patients 18 years of age or older requiring a CVC were included. The rate of mechanical complications not including failure to place was 14%. Complications included failure to place the CVC (n = 86), arterial puncture (n = 18), improper position (n = 14), pneumothorax (n = 5 in 258 subclavian and internal jugular attempts), hematoma (n = 3), hemothorax (n = 1), and asystolic cardiac arrest of unknown etiology (n = 1). Male patients had a significantly higher complication rate than female patients (37% vs 27%, P = .04). The subclavian approach had a higher complication rate than the internal jugular or the femoral approach (39% vs 33% vs. 24%, P = .02). The complication rate increased with the number of percutaneous punctures, with a rate of 54% when more than 2 punctures were required.