STUDY DESIGN: A retrospective study OBJECTIVES: To examine the mid term clinical and radiologic findings of patients treated by Posterior Lumbar Interbody Fusion (PLIF) with cages in spondylolisthesis. LITERATURE REVIEW: The clinical result of PLIF with cages is satisfactory. PLIF with cages is a useful treatment for spondylolisthesis. MATERIALS AND METHODS: Forty-two patients were followed up for more than 5 years. Their mean age was 53 years and the mean follow-up period was 68 months. Twenty-one cases were the isthmic type, and 21 cases were the degenerative type. The low back pain score, Lin s clinical result, perioperative value of slippage, anterior intervertebral disc space height, radiological change in the adjacent level and complications were evaluated. RESULTS: The preoperative lower back pain score improved from 46.7 to 86.4 points at the last follow-up (p.0.05). Thirty-eight patients (91%) showed excellent or good results. The preoperative value of slippage improved from 17.5% to 5.7% (p.0.05). The anterior intervertebral disc space height increased from 10.0 to 14.5 mm (p.0.05). There were changes in the above and lower adjacent segments in 12 cases (28%). Two of these cases required surgery. CONCLUSIONS: PLIF with cages might be an effective method in spondylolisthesis. However, the long-term follow-up showed changes in the adjacent segment.