Leiomyosarcoma of the vascular origin is a rare malignant tumor. It originates from the smooth muscle cells of the media with intra- or extraluminal growth, and in most cases it arises in the inferior vena cava. The diagnosis is often delayed because the clinical symptoms of this disease are often nonspecific. Accurate diagnosis of inferior vena cava leiomyosarcoma (IVCLMS) needs histologic confirmation. We report a case of IVCLMS histologically confirmed by aspiration biopsy with a catheter during digital subtraction angiography presenting with pulmonary emboli in a 65-year-old man.