The widespread use of MRI in the assessment of low back pain has led to increased detection of degenerative cysts of the spine, which was essentially a surgical diagnosis earlier. The awareness of degenerative cysts, the significance of their role in the etiology of radicular and back pain and their effective management is evolving. We describe a case of bilateral, gas-filled lumbar facet synovial/ ganglion cysts causing focal arachnoid inflammation and lateral lumbar canal stenosis.