We tried neurological and histological assessment for the model of the chronic compressed cauda equina in the rat to clarify pathophysiology of the chronic compressed cauda equina. After L4 laminectomy under anesthesia, a silastic sheet (0.3 mm thick) was inserted into the epidural space. Pre- and post-operation, the Plantar test and the Treadmill test were performed until 24 weeks. The Plantar test showed no significant difference between the experimental and control group. In the Treadmill test, walking duration decreased gradually in the experimental group to 64% of the control at 24 weeks after the operation. The number of large diameter axons decreased in the experimental cauda equina.