Sacral perineural cyst is one group of extradural meningeal cyst at the sacral region. These lesions are distinguished from other spinal cysts because perineural cyst does not communicate with subarachnoidal space. Fluid filled cysts may compress adjacent nerve roots causing low back pain and sciatica which are dramatically improved by surgical excision. Differential diagnosis from other cysts can be accomplished by failure of collection of dye into cyst by initial myelography. C-T myelography rules out other mass lesions and often reveals communication of perineural cyst that filled with contrast medium. Magnetic resonance imaging well demonstrates three dimensinnal configures of an intraspinal cystic mass in initial study. However it is important to recognize that these cysts are one of causes of radiculopathy. We report three cases of sacral perineural cysts with radiculopathy.