Case report. We report a case of hydrocephalus as a complication of durotomy during cervical laminoplasty. Hydrocephalus is a very rare complication of cervical laminoplasty. A 72-year-old man had an incidental durotomy during cervical laminoplasty. The dural leak was repaired by secondary surgery. However, the patient continued to complain of headaches and developed confusion and drowsiness. A computed tomographic scan of the brain showed hydrocephalus. After insertion of a lumbar drain, the patient experienced a temporary improvement in the neurologic symptoms. After 6 months, the neurologic symptoms recurred and a ventriculoperitoneal (VP) shunt was placed. After placement of the VP shunt, the neurologic symptoms improved significantly. If a patient shows deterioration of neurologic symptoms after an incidental durotomy, surgeons should consider the possibility of hydrocephalus.