The natural history of cervical spondylotic myelopathy in a series of 55 patients resulted in a moderate to severe disability during a mean period of 45 months. Results of operation for myelopathy indicated improvement in one group that was maintained for a mean of 85 months. In another group, progressive worsening occurred after operation, or late worsening occurred, in some instances as long as 8 to 12 years after improvement and plateau. Patients with cervical spondylotic radiculopathy tended to be separated from those with myelopathy with respect to presentation, symptom complex, and operative result. Results of operation for radiculopathy were consistently good. A worsened disability postoperatively for patients with cervical spondylotic myelopathy was associated with the preoperative symptom of sphincter disturbance and the sign of lower extremity weakness. Change in hand movement after operation for myelopathy and change in distance walking ability were not correlated with numerous preoperative factors. A trend of improvement in disability following anterior interbody fusion and a tendency to worsen in disability following all varities of laminectomy were significant.