We report a girl with Wolfram syndrome who presented with juvenile-onset diabetes mellitus when she was 4 3/12 years old. Optic atrophy and high frequency sensorineural hearing loss were found at 7 and 9 5/12 years of age, respectively. Her younger brother also developed Wolfram syndrome when he was 3 2/12 years old. Wolfram syndrome is also called DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy and deafness). This syndrome is transmitted as an autosomal recessive trait and is a progressive neurodegenerative disorder. It should be considered in a diabetic patient with unexplained optic atrophy, hearing loss, or polyuria and polydipsia in the presence of adequate blood glucose control. Visual acuity should be checked annually in patients with juvenile-onset diabetes mellitus. Optic atrophy should be considered if visual acuity is impaired.