Object The multilevel oblique corpectomy (MOC) allows widening of the spinal canal and foramen trough via an anterolateral access to the cervical spine with control of the vertebral artery and does not require vertebral stabilization or fusion. In the present study, the authors' goal was to demonstrate the long-term efficacy and safety of MOC in the treatment of selected cases of spondylotic myelopathy. Methods The authors conducted a prospective study in a series of 268 patients who underwent MOC for cervical spondylotic myelopathy over a 14-year period. Preoperative and postoperative neurological functioning were evaluated with the modified Japanese Orthopaedic Association scale. Spinal stability was assessed in all patients on serial plain and dynamic cervical radiographs at the last follow-up. The degree of canal expansion after MOC was also measured using the spinal canal/vertebral body ratio, and directly by measuring the diameter of osseous canal on pre- and postoperative CT scans and high-resolution MR images. Results At a mean follow-up of 96 months, clinical improvement was recorded in 86.6% of patients with a global recovery rate of 87.6%, clinical stability in 8%, and worsening in 5%. Long-term spinal stability was demonstrated in 98% of patients. Conclusions Multilevel oblique corpectomy was demonstrated to be a safe procedure that provided good results in terms of improved functional status and long-term spinal stability.