STUDY DESIGN: Retrospective study. OBJECTIVES: The purpose of this study was to investigate whether preoperative sagittal alignment and range of motion (ROM) affect adjacent segment degeneration (ASD) and disease after anterior arthrodesis in degenerative cervical spinal disorders. Summary of Literature Review:There is no study about the relationship between preoperative ROM and sagittal alignment and the development of ASD yet. MATERIALS AND METHODS: We took a retrospective approach to study 136 patients who underwent an anterior arthodesis for less than 2 segments with PEEK cage and plate construct method for degenerative cervical diseases and who have a minimum of 3 years of follow-up. We analyzed ASD and cervical ROM, such as less than 40degrees(group A) and more than 40degrees(group B) and sagittal alignment, such as lordosis or kyphosis with less than 10degrees(group a), 10degrees~30degrees(group b) and more than 30degrees(group c). Adjacent segment degeneration was graded according to Park's classification and Hillibrand method. RESULTS: There was no statistically significant difference between group A(1.35+/-0.48) and group B (1.44+/-0.50) in the correlation between the cervical ROM and the variation of disc height(p=0.07). Concerning the relationship between the ROM and osteophyte formation on adjacent segment, no statistically significant difference has been found between group A(1.64+/-0.88) and group B(1.43+/-0.67) (p=0.06). The disc height change at the final follow up after cervical sagittal alignment showed no statistically significant difference among the groups: Group A presented with 1.53+/-0.50, group B with 1.30+/-0.46 and group C with 1.40+/-0.50.(p=0.08) Regarding sagittal alignment and osteophyte change, there was no statistically significant difference among the groups as group A showed an average of 1.33+/-0.48, group Ban average of 1.56+/-0.88 and group Can average of 1.60+/-0.82(p=0.07). CONCLUSION: Although the preoperative sagittal alignment and ROM did not significantly affect adjacent segment degeneration and diseases in a mid-term follow-up evaluation after anterior arthrodesis with PEEK cage and plate in degenerative cervical spinal disorders, we think a future study is required with a sufficient number of patients and a long term follow-up because there were borderline statistical significances shown in the present study.