A complete surgical resection is the only proven therapeutic modality that prolongs the survival in patients with leiomyosarcoma of the inferior vena cava (IVC). Reconstruction of the IVC is not always necessary but is often required to facilitate venous drainage of the kidney for the tumors at the pararenal area of the IVC. Controversy exists in postoperative adjuvant therapy. Recently, we experienced four cases of pararenal leiomyosarcoma of the IVC, of which treatment consisted of a complete resection of the tumor, ringed polytetrafluoroethylene (PTFE) graft interposition, and bilateral renal vein reconstructions in all patients. Postoperative radiation therapy was instituted in 3 of 4 patients. One patient who did not receive the postoperative radiation therapy was treated with adjuvant chemotherapy. The kidneys were preserved in all patients and no deep vein thrombosis (DVT) or venous insufficiency of the lower extremity veins developed. Distant metastasis to the lung was noted in one patient at 18 months after surgery, who was not received the postoperative radiation therapy but chemotherapy. In conclusion, a complete resection of the tumor, IVC reconstruction, and bilateral renal vein reconstruction followed by adjuvant radiation therapy is recommended for the treatment of pararenal leiomyosarcoma of the IVC.