Disc fragment migration occurs in 35%-72% of lumbar disc herniations. Most of the herniated disc fragments migrate in the rostal, caudal and lateral directions. Posterior epidural disc fragment migration is a rare finding and posterior migration causing Cauda Equina syndrome is exceptionally rare. We report here on two cases of L4-5 disc fragment posterior epidural migration that caused Cauda Equina syndrome, and this was diagnosed by performing radiological examination, and we also include a review of the related literature.