Degenerative spondylolisthesis, which occurs frequently in middle-aged women, is a disease that causes canal stenosis of the lumbar spine and low back pain. Although the clinical features have been described characteristically, its pathogenic mechanism and therapeutic principles are still to be clarified. Some investigators have claimed that the disease originates from morphologic abnormalities of laminae and facet joints or that it is primarily due to degeneration of the intervertebral disks and degenerative changes of the facet joints. We selected two groups of patients retrospectively. The one was a group of patient who had normal findings on their magnetic resonance imaging(Group I ) and the other was a group of patients who showed degenerative spondylolisthesis at L4-5 and had been managed surgically(Group II ). We measured the total lordosis from Ll to S 1 and segmental lordosis of L3-4, L4-5 and LS-S 1 in both groups by Cobbs method. In group 3, we measured the degree of slippage of the L4 vertebral body and investigated the associated congenital anomalies of the lumbosacral vertebra on simple anteroposterior and lateral radiographs in both groups. And we measured the facet joint angles of the L3-4, L4-5 and L5-Sl at both side on MRI. Then we analysed the results statistically and got the following conclusions.