Venous (pseudo)aneurysms are rare entities. Herewith we report a case of the right lower extremity in a 42-year-old woman in whom a non-pulsatile mass was diagnosed only by physical examination as a hematoma and was treated conservatively. Six months later ultrasound and phlebography identified a pseudoaneurysm of the great saphenous vein. Post-traumatic venous pseudoaneurysm should be considered among the differential diagnostic options of a subcutaneous non-pulsatile mass in patients with a history of physical trauma. Surgery was offered which was rejected by the patient. Further one month follow-up showed no change.