It is well recognized that case management is required to survive in the rapidly changing medical environment. One of the case management is the critical pathway(CP) which is assumed to increase the quality of care and at the same time to decrease the length of stay in hospital. The purpose of the study was to develop a CP for the management of patients with postero-lateral fusion for lumbar spinal stenosis. Through review of literature and medical records of patients with spinal stenosis, a pilot CP was designed, including 8 different care components such as medication, laboratory tests, assessment etc., from one day before surgery to 6 days of postoperative care. Every item of the pilot CP was evaluated by a panel of experts to test the content validity. The items not agreed on by more than 4 out of 6 experts were deleted or modified to be integrated in the CP. To apply the modified CP to a clinical environment, the items reflecting treatment, medication and lab work were entered into an order communication system(OCS), and doctors and nurses were taught to use the CP. Finally, the development of CP for the patients with posterolateral lumbar fusion was completed after the application and variance analysis of the CP.