A 21-year-old woman presented with cervical myelopathy due to nontraumatic cervical disc herniation associated with cervical canal stenosis. The patient underwent removal of the herniated disc and anterior fusion with an autogenous iliac crest bone graft. After surgery, the patient showed satisfactory improvement. Cases of cervical disc herniation in our center and reported cases without cervical trauma in either young adults or in childhood were reviewed retrospectively. We discuss the pathogenesis of cervical disc herniation in our young patient in the context of these other cases. Cervical disc herniation rarely occurs before the age of 30 years. A history of cervical trauma and preexisting fusion of the cervical spine are risk factors for cervical disc herniation. The present case is the youngest known of nontraumatic disc herniation without other underlying disease. Hypermobility due to neck cracking and a relatively narrow spinal canal might have been important in causing cervical myelopathy by disc herniation.