We describe a case of diplopia due to abducens nerve palsy after upper cervical spinal surgery. A 22-year-old woman presented with a chief complaint of numbness and weakness in her left hand. A spinal cord tumor was detected at the C1/2 level. These complaints disappeared after resection of the spinal cord tumor; however, she presented with diplopia due to abducens nerve palsy 3 days after surgery. Brain computed tomography and magnetic resonance imaging revealed no abnormalities. Within 1 month there was complete spontaneous resolution of the abducens nerve dysfunction. It is important for spinal surgeons to be aware of cranial nerve palsy as a potential complication of cervical spinal surgery.