Primary iliac vein aneurisms are extremely rare being described as anomaly, without any history of trauma, cardiovascular pathology or arteriovenous fistula. This clinical condition has a high rate of potentially fatal complications: pulmonary embolism; ruptured aneurism; deep vein thrombosis. There are only 7 cases of iliac vein aneurism described in the literature. We describe an additional case of a 59-year old patient presented with abdominal pain, right lower limb edema and palpable mass in the right iliac area. Ultrasound (US) revealed a liquid formation, confirmed by computed tomography (CT). Surgical removal of the aneurism with lateral venorrhaphy was performed. Postoperative evolution was uneventful. The patient is asymptomatic during 36 month follow-up.