To my knowledge, no general study of complete ophthalmoplegia is available. This study was performed to determine the seats and causes of bilateral ocular paralysis. The personal records of 13 440 neurology and neurosurgery inpatients were reviewed. Eighteen (58%) of 31 patients had Fisher syndrome (13 cases) or Guillain-Barré syndrome (5 cases). Four cases resulted from midbrain infarction, 3 from myasthenia, and 1 each from pituitary apoplexy, skull base metastasis, botulism, mucormycosis, phenytoin toxicity, and trauma. Many conditions produce complete ophthalmoplegia on rare occasions, but Fisher syndrome, which paralyzes the eyes in nearly one third of cases, was by far the commonest cause.