The morphological characteristics of samples of scalp hair from normal children and adolescents (8-17 years) and from a group of diabetic children (8-11 years) were determined. In normal children, there were no sex differences. Significant increases in the diameters of both bulb and shaft were found when prepubertal (8-11 years) and pubertal (12-17 years) groups were compared. Diabetic females had smaller bulb diameters and diabetics of both sexes had reduced shaft diameters in comparison to normal children of similar age. These findings suggest previous nutritional deficits in male and female diabetics and the possibility of continued nutritional problems in the females.