Synovial cyst is a rare degenerative lesion and especially occurs in old age. Generally, it is more prevalent in the lum- bar spine and especially at L4-L5 levels in female patients. A 67-year-old female patient admitted our hospital with left radiculopathy. Her neurological exam was consistent with radiculopathy. Lumbar magnetic resonance imaging revealed cystic lesion which was originating from the left facet joints synovia at L4-L5 level and the dura and the L5 nerve root was compressed by cystic lesion. Cystic mass was totally excised with left L4 partial hemilaminectomy and flavectomy. The patient’s symptoms were improved in early postoperative periods. Synovial cyst should be considered in the differential diagnosis, especially in elderly female patients with radiculopathy, and surgical excision of symptomatic patients should be treated primarily.