A ganglion cyst is a tumor-like lesion that contains mucous or myxoid material in the fibrous capsule. We report a case of ganglion cyst located in the lumbar anterior epidural space and causing lumbar radiculopathy. Computed tomography and magnetic resonance imaging revealed the cyst as a cystic lesion with wall en-hancement. Myelography showed that it was not filled with contrast medium and not connected with the dura, nerve root, or facet joint.