Spondylolisthesis is defined as forward slipping of a vertebral body on another, and this slipping causes a spectrum of symptoms from mild back pain to overt spinal stenosis. It comprised about 20 % of the low back surgery cases performed at our department during the past ten years. This study was performed to compare the clinical results of the listhesis patients treated with various surgical methods, to determine the validity of reduction of olisthesis and to determine the optimal treatment modality for spondylolisthesis. One hundred and ninety-two patients with spondylolisthesis treated surgically at SNUH during the ten year period of 1980-1989 were analyzed and following results were obtained. 1. Most of our surgical series were operated on for spinal stenosis with moderate to severe claudication. Those with just mild listhesis and back pain were treated conservatively. 2. The clinical results were not significantly influenced by the method of surgical treatment or the degree of reduction as long as decompression for spinal stenosis has been adequated in the cases combined with stenosis. 3. The rigid internal fixation with transpedicular screws offered the best result with short segment fusion, early ambulation, restoration of the lumbar lordosis and short hospitalization. 4. Authors suggest that grade I, III olisthesis be treated with posterolateral fusion with pedicle screws, with or without reduction and in grade III, IV, posterolateral fusion or posterior interbody fusion with pedicle screws with reduction. In conclusion, surgical treatment of spondylolisthesis is best accomplished by use of transpedicular screws in the aspect of reduction, restoration of lumbar sagittal curvature and early postoperative mobilization.