Concurrent use of instrumentation has been shown to increase fusion rates and satisfactory results for surgical treatment of the lumbar stenosis. The objectives of the present study were to evaluate clinically and radiologically two groups of lumbar stenosis who were surgically treated with pedicular screw fixation system and posterior lumbar interbody or posterolateral autogenous bone graft following complete posterior decompression. One group was degenerative type and the other group was spondylolisthetic type spinal stenosis. We analyzed the results of 39 cases of lumbar stenosis who underwent pedicular screw and rod fixation system and posterior lumbar interbody or posterolateral autogenous iliac bone fusion following complete posterior decompressive operation during the period from May 1988 to December 1992. There were 27cases of degenerative type and 12 cases of spondylolisthetic type lumbar stenosis. The were 25 women and 14 men. Their age was ranged 20 to 76 years old with an average of 51.7 years old. The follow up period was the interval from 18 months to 6 years with an average of 3.2 years. The radiologic union rate was average 94.9% and 96.3%(26cases) in degenerative spinal stenosis and 91.7%(11 cases) in spondylolisthetic spinal stenosis. The clinical success rate was average 92.3%(36 cases), 88.9%(24 cases) in degenerative spinal stenosis and 100%(12 cases) in spondylolisthetic spinal stenosis. The patients with spondylolytic spinal stenosis showed better result in their life than the patient with degenerative spinal stenosis.