lntroduction : lsolated venous aneurysm is defineci as an focal vascular dilatation that communicates with normal size venou s stru cture through a single channel, and it should not have any association with an arteriovenous communication ora pseudoaneurysm. Venous aneurysms may rarely bethrombosed. Here we present a female patientwith thrombosed venous aneurysm of the small saphenous vein.Case Report: A 49 year-old woman was admitted to our hospital with complaints ofa growing mass at the left popliteal region during the last 18 months. Physical examination revealed a firm subcutaneous mass on the left popliteal region. Color tlow duplex imaging (CFDI) confirmed thrombosed saccular venous aneurysm of the small saphenous vein extending to the saphenopopliteal junction (SPJ) t h at measured approximately 3.2 cm in diameter. Surgical intervent ion was performed under spinal anesthesia . The aneurismal mass was relatively thin walled and was occluded by blood clot. Her postoperative course was uneventful and her symptoms resolved. Histologi c findings were consistent withvenous aneurysm.Conclusion: in order to prevent the risk of deep venous thrombosis and even pulmonary embolism, we think that thrombosed venous aneurysms close to the saphenopoplitealjunction should be operated without delay.