Leiomyosarcoma of the inferior vena cava (IVC) is an uncommon neoplasm, most frequently seen in the sixth decade with a female predominance. Imaging modalities allow an early and accurate preoperative diagnosis resulting in a higher rate of surgical resection and improved survival. Imaging findings in a 65-year-old woman with leiomyosarcoma of IVC are described. Computed tomography and MRI typically showed a non-fatty, necrotic intraluminal IVC mass with extension to retroperitoneal compartments. Cavography was useful to evaluate the collateral circulation associated with the extensive intraluminal mass. The lesion was biopsied under ultrasound guidance.