Aim and background: Internal jugular central venous catheter insertion is a common procedure in the intensive care unit. Complications and malpositioning are infrequent when performed under ultrasound guidance. We discuss the dilemma created by anatomical variation during central venous catheter placement. Case description: A 66-year-old woman underwent left internal jugular central line insertion under ultrasound guidance. Given the anatomical course of the vascular catheter as seen on the chest X-ray, blood gas analysis sampling through the same revealed venous values. High-resolution computed tomography of the chest showed the vascular catheter located in the left superior vena cava (LSVC). Conclusion: Intensivists need to be aware of vascular anomaly and anatomy associated with persistent LSVC to lessen the risk of complications associated with vascular cannulation. Clinical significance: Asymptomatic persistent LSVC can be detected during vascular procedures. Intensivists need to be aware of this asymptomatic anomaly as handling of the coronary sinus during procedures can lead to dysrhythmias and hemodynamic instability.