Wrong-level spine surgery, in which an operation is performed at a vertebral level different from the intended one, is a rare but serious complication with wide-ranging medical and legal effects. Although many protocols have been developed to prevent such a serious unfavorable event, the problem has not yet been eliminated. Research into the effectiveness of strategies to prevent wrong-level spine surgery is lacking. Herein, we describe a case of 44-year-old woman presented with neck pain and bilateral upper extremity weakness and numbness. Magnetic resonance imaging showed C5/6 and C6/7 disc herniations with spinal cord compression. The patient underwent anterior cervical discectomy and fusion; however, at the conclusion of the surgery, intraoperative radiographs showed that it was accomplished at C4/5 and C5/6-one level above the intended level. On the basis of this case and similar ones, a new protocol was developed that included implementation of a Spine Level Safety Checklist to document the reference point, the landmark, and the level of exposure that is marked on the intraoperative radiograph. Since implementation of this protocol, the incidence of wrong-level spine surgery at the senior author’s institution has decreased from 4/7000 to 0/11,200. Adoption of this protocol by other centers is thus recommended to reduce the incidence of such complication.