Intraspinal synovial cyst of the lumbar spine is an uncommon degenerative lesion near the facet joint. Clinical manifestations and magnetic resonance images (MRI) of five patients with lumbar radiculopathy were retrospectively reviewed. Extradural, juxtafacet cystic lesions were noted on MRI all the patients and they presented on MRI as fluid-containing lesions with close relation to the facet joints. Two patients received conservative treatment and the symptoms were subjectively relieved. Subsequent MRI examinations of these two patients did not show the cystic lesions. Posterior decompression with excision of the cyst was performed on the other three patients and the symptoms were resolved after the operations. The diagnosis of synovial cyst may be considered in patients with chronic lumbar radiculopathy and the MRI findings showing juxtafacet cystic lesions, and the lesions become smaller or disappear after conservative management.