Background: Degenerative spondylolisthesis is defined as forward slippage of a vertebra with respect to the underlying vertebra, without rupture of the posterior arc, distinguishing it from lytic spondylolisthesis. It thus usually induces lumbar canal stenosis. There is, however, no strong consensus regarding the various medical and surgical treatments available. Objective: To assess the long-term clinical results of decompression alone and decompression plus fusion, for degenerative spondylolisthesis. Patients and methods: We randomly assigned 63 patients who had lumbar spinal stenosis due to degenerative spondylolisthesis at the L4/5 level to undergo either decompression alone (decompression group), decompression plus fusion (fusion group). Three patients refused to undergo randomization; therefore, the remaining 60 patients were randomly assigned. Results: In total, 60 patients underwent randomization. The follow-up rate at 3 years was 85%. The fusion group showed higher blood loss, longer postoperative hospital stay and a longer operative time than the decompression group. As regard clinical outcomes, all scores significantly improved in the postoperative period and these outcomes were maintained at 3 years postoperatively in each group. There were no significant differences found among the two groups at 1 and 3 years postoperatively. Conclusion: Decompression plus fusion does not have better results than decompression only in the management of patients with lumber spinal stenosis with low grade degenerative listhesis.