Duplication of the inferior vena cava( IVC) is only rarely reported and often detected as an incidental finding(0.5-3%). In our patient, anomolous vessel continuation left iliac vein crossing anterior to aorta, joining right IVC at level border L1 vertebra.The association with a prothrombotic state,was exacerbated after splenectomy for this patient who had sickle cell anemia.