Objective: We have conducted a prospective study to evaluate the results and effectiveness of bilateral decompression via a unilateral laminectomy in 50 patients with 98 levels of degenerative lumbar spinal stenosis without instability.Methods: Clinical outcomes were assessed using the Visual Analog Scale, Oswestry Disability Index, Short Form-36, and subjective Satisfaction Measurement.Results: Adequate decompression was achieved in all patients. The mean follow-up time was 22.8 months (range 19 - 47 months). Surgical decompression resulted in a dramatic reduction of overall pain in all patients (late postoperative VAS score was 2.16 +/- 0.81). The ODI scores decreased significantly in early and late follow-up evaluations and the SF-36 scores demonstrated significant improvement in late follow-up results in our series. Patient satisfaction rate was 94%, and its improvement rate was 96%.Conclusion: For degenerative lumbar spinal stenosis with or without mild degenerative spondylolisthesis, the unilateral approach allowed sufficient and safe decompression of the neural structures and adequate preservation of vertebral stability, resulted in a highly significant reduction of symptoms and disability, and improved health-related quality of life.