Juxtafacet cyst of the spine is a rare occurrence. Reports have described them as synovial cysts; ganglion cysts; extradural cysts as well as degenerative cysts of the spine. Patients may present with radicular pain, motor deficits, sensory disturbances, cauda equina syndrome and even myelopathy. Lumbar juxtafacet cysts may be confused clinically with prolapsed intervertebral discs or other conditions involving nerve root compression such as arachnoid cysts, ependymal cysts, dermoid cysts or teratomatous cysts. In the case of the juxtafacet cyst, surgical excision is usually curative. We report a case of spinal synovial juxtafacet cyst found intraoperatively in a case that was preoperatively diagnosed as prolapsed intervertebral disc. Synovial juxtafacet cyst of the spine should be considered as one of the differential diagnoses in patients, especially in older patients, presenting with nerve root compression.