We report a case of cauda equina syndrome caused by Gnathostoma spinigerum, which was confirmed by an immunoblotting test. MR imaging of the lumbosacral spine showed long, segmented hyperintensity along the cauda equina with irregular enhancement on the postcontrast study. The conus medullaris was slightly enlarged with abnormal enhancement. The patient was treated with corticosteroids, and her clinical condition improved. MR imaging, 9 months after treatment, showed the condition to be completely resolved.