Vascular leiomyosarcomas are rare tumors, and only 21 have been described as developing in the systemic arteries. We present a case, the sixth in the literature, of a leiomyosarcoma originating in the popliteal artery of a 67-year-old woman treated with en bloc excision of the neoplasia and the artery followed by a popliteal tibioperoneal trunk bypass. The patient then was underwent adjuvant radiotherapy and chemotherapy. After 31 months of follow-up, the patient has mild claudication but does not have either recurrence or metastasis.