This retrospective study of 55 shunted patients with "normal pressure" hydrocephalus evaluates the surgical results. Sixty percent of these patients had objective improvement following cerebrospinal fluid diversion but 44% had shunt-related complications of which 9% were fatal. Those patients who received a single theco-peritoneal shunt had a higher improvement rate and a lower incidence of postoperative complications. Successfully treated complications did not preclude postoperative improvement.