Cervical spondylosis is associated with myelopathy and radiculopathy, which sometimes mimic clinical manifestations of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder that affects upper and lower motor neurons. Cervical spondylosis may coexist with ALS because both diseases preferentially affect individuals of middle or old age. We investigated 63 patients with ALS to clarify the complications of cervical spondylosis and other spinal disorders and to explore the history of surgical treatment for them. We found cervical spondylosis in 30 patients (48%), lumbar spondylosis in 7 (13%), ossification of the posterior longitudinal ligament (OPLL) in 4 (6.3%), and ossification of the yellow ligament (OYL) in 4 (6.3%). Surgery was performed early in the course of the disease on the cervical spine in five patients (7.9%) and on the lumbar spine in one (1.6%); these patients consulted our clinic because their motor symptoms had progressed even after the spinal surgery. Our results indicate that nearly half of all ALS patients have their disease complicated by cervical spondylosis, and that a careful differential diagnosis for ALS is necessary before making decisions about spinal surgery.