We report a case of a leiomyosarcoma of the inferior vena cava (IVC) which continued to grow after the resection, despite aggressive radio-chemotherapy. A 54-year-old woman was admitted to a hospital for investigation of right lower abdominal pain and lumbago. A diagnosis of leiomyosarcoma of the IVC was made by echo examination and she was transferred to our hospital for treatment. Abdominal CT, MRI, and vena caval contrast studies showed a tumor with the maximum diameter of 5cm. We resected the tumor, preserving the right renal vein and right side wall of the IVC, and reconstructed the IVC using a modified 20mm-ringed ePTFE graft. Pathological examination confirmed the diagnosis of leiomyosarcoma. A CT scan of the abdomen done 4 months later showed a 4cm lesion of local recurrence and radio-chemotherapy was started, however, the patient died 225 days after the operation. IVC sarcomas have a high recurrence rate and they are generally resistant to radio-chemotherapy, so that surgery is primarily employed. Some new treatment strategy is needed for unresectable and recurrent IVC tumors.