Thirty-six patients with degenerative lumbar spondylolisthesis presenting stenotic symptoms underwent fusion after decompressive laminectomy. There were 34 women and 2 men. The mean age of patients was 47 years. During surgery reduction was achieved by manipulating the operation table. Discectomy was performed after decompressive laminectomy procedure in 11 of 36 patients. The mean follow-up time was 19 months. On the plain radiographs slip distance, disc height and disc space angle were measured pre- and post-operatively and at the last follow-up to assess the degree of olisthesis and its maintenance. The postoperative segmental stability and overall clinical results in these patients were evaluated, and summarized as follows: l. After operation, slip reduction was obtained in 26 to 36 patients (reduction rate; 78%). Postoperative slip distance (mean, 1.9±2.2mm) was significantly decreased, while immediate postoperative disc height(mean, 13.1±2.2mm) and disc space angle (mean, 4.0±4.5mm) were significantly increased. 2. At the last follow-up slippage did not progress (t=0.06, p>0.05), but disc height and disc space angle significantly decreased(height; t=7.38, p<0.01, angle; t=4.8, p<0.01) from immediate postoperative values. There were no significant differences in decrease of disc height and disc space angle in patients with or without discectomy, and between the groups of the different pedicle screw fixation systems. 3. Fusion was obtained in 28 of 38 patients(fusion rate; 78%). Hardware failure was noted in 8 patients (metal failure rate: 22.2%). 30 patients had successful clinical outcome (83.3%). There was no significant difference in fusion rate, hardware failure and clinical results according to the amount of postoperative slip reduction and gaining of disc height, discectomy and the type of pedicular fixation systems.