Central vein catheterisation of left Internal jugular vein was done under Ultrasound guidance. Post procedure chest Xray revealed abnormal position of central vein catheter tip and created confusion about its correct placement. Following confirmatory chest CT scan , it was found to be in persistent left sided superior vena cava. Its a common congenital thoracic venous anomaly. Hereby discussing case report of persistent left sided superior vena cava and its clinical implications.