We report the case of a 57-year old male patient who was admitted to the polytrauma unit of our hospital following a car accident. As an incidental finding on a whole-body CT scan, the patient was found to have a persistent left inferior vena cava, unrelated to cardiopulmonary conditions or the azygos vein. This is a very rare anatomical variant, but one of great surgical interest, as it can influence the dissection plane during surgery, and its injury may lead to high morbidity and mortality.