Aneurysms of the portal vein and its branches have been rarely described. Their natural history is unknown although large ones (>3 cm in diameter) have been reported to cause rupture, thrombosis, duodenal or biliary obstruction, inferior vena cava compression and/or portal hypertension. We report the case of an incidentally diagnosed 4.5 cm splenic vein aneurysm repaired by endovascular treatment through a transhepatic route. The aneurysm was successfully excluded using a covered stent (Viabahn, Gore). The transhepatic route opens the possibility of offering a minimally invasive approach to vascular lesions of the portal vein system.