PURPOSE: We studied to determine whether the degenerative spondylolisthesis has rotary deformity in addition to forward displacement. MATERIALS AND METHODS: We have made an analysis of difference of rotary deformity between the 31 study groups of symptomatic degenerative spondylolisthesis and 31 control groups without any symptom,statistically. We also reviewed CT findings in 15 study groups. RESULTS: The mean rotary deformity in study groups was 6.1 °(the standard deviation is 5.20), and the mean rotary deformity in control groups was 2.52 °(the standard deviation is 2.16)(p <0.01) CONCLUSION: The rotary deformity can be accompanied with degenerative spondylolisthesis. We may consider the rotary deformity as a cause of symptomatic degenerative spondylolisthesis in case that any other cause is not detected.