Purpose: To investigate the reliability of intra-atrial electrocardiogram (ECG) use for external jugular vein (EJV) catheterization. Materials and Methods: Patients undergoing open heart surgery in Suleyman Demirel University Hospital between February and June 2006 were included in the study. Using a sterile Seldinger technique, a triple lumen polyurethane central venous catheter was introduced (Certofix (R) Trio V 720, length 20 cm, 7 French) under intra-atrial ECG guidance. The presence of an increase in P-wave size was recorded. Just after the surgery, a portable chest X-ray was taken. The method was considered to be successful when a change in P-wave could be seen and the catheter was in the superior vena cava, as well as when there was no change in P-wave and the catheter was not in the superior vena cava. Results: In six patients (12%), we were not able to advance the guidewire. In the remaining 44 patients, the catheter was inserted without problem. Eight of these 44 catheters were positioned in the innominate vein, with a malposition ratio of 18%. The success rate of external jugular vein cannulation with intra-atrial ECG was 95%. No complications occured related to the EJV cannulation. Conclusion: Considering that it is easily accessed without complication, and the malposition is successfully detected by intra-atrial ECG, EJV is a suitable access for central venous cannulation when internal jugular vein (IJV) is not usable.