Persistent left superior vena cava (PLSVC) is the most common thoracic venous circulation anomaly and discovered incidentally during hemodialysis catheter insertion. PLSVC may have some clinical implications for nephrologists. PLSVC can create difficulties during catheter insertion and cause serious complications; it can be mistaken for placement into other sites and cause inappropriate response such as catheter removal. Nephrologists who place hemodialysis catheters in the left jugular or subclavian vein should be aware of the existence of PLSVC.