The records of 2,200 patients who were admitted to a general hospital psychiatric service and of 475 patients with brain tumors were examined to determine how frequently early neurological diseases were mistaken for psychiatric disorders. From the former, it was learned how often neurological disease had been either overlooked or misdiagnosed at the initial psychiatric admission. The second group of records showed whether these cases had been erroneously diagnosed before the brain tumor was discovered. There were no instances of misdiagnosed neurological disease in either group. Among the first group of patients, there were two incomplete diagnoses and one false incorrect diagnosis.