Primary venous leiomyosarcoma is rare, only 197 patients have been reported. To examine progress in diagnosis, treatment, and clinical outcome, we retrospectively reviewed data of 13 patients, 12 women and one man (mean age, 55 years; range, 19 to 75 years), who in the last 35 years underwent surgical treatment for primary venous leiomyosarcoma at our institution. The tumor arose from the inferior vena cava in eight, iliac vein in two, ovarian vein in one, and greater saphenous vein in two patients. Primary venous leiomyosarcoma was detected by physical examination in nine patients, symptoms were present in six. The 13 patients underwent 16 surgical procedures to resect primary (12), recurrent (2), or metastatic (2) tumors. Local excision alone was performed in seven, and local excision with reconstruction of the inferior vena cava or iliac vein was performed in six patients. The tumor was greater than 10 cm in eight patients. The perioperative mortality rate was 15% (2 of 13). Median survival of the 11 early survivors was 3.5 years (range, 6 months to 17 years). Currently five patients are alive (four of them free of known tumor), with a median survival of 3 years (6 months to 17 years) after surgery. Of the eight deceased patients, primary venous leiomyosarcoma recurred after resection in six. Tumor recurrence was not affected by tumor grade, size, or adjuvant treatment. Although early detection with modern imaging techniques could potentially be of benefit, wide local excision with selective venous reconstruction affords the only hope for prolonged survival.