Aneurysms involving the distal radial artery are rare lesions which are usually secondary to penetrating trauma or iatrogenic injury. Blunt trauma is an extremely uncommon cause. In the absence of a history of penetrating vascular injury, a radial artery aneurysm may easily be misdiagnosed as a nonvascular mass such as a synovial cyst. A diagnostic approach to these lesions is discussed emphasizing the role of noninvasive studies in uncomplicated cases. Excision of the aneurysm is recommended. The decision to ligate or reconstruct the radial artery remains controversial.