Four patients with diabetes mellitus, optic atrophy, and high-frequency neurosensory hearing loss, two of whom also had diabetes insipidus, are described. The frequency of this syndrome among patients with juvenile diabetes appears to be between 1/148 and 1/175. Because of the progressive nature of the disabilities and the autosomal recessive mode of inheritance, careful monitoring of all juvenile diabetic patients for other signs of the syndrome is warranted.