Thirty-four children were observed prospectively during a period of 5 years from the onset of diabetes regarding height, weight and subcutaneous fat in relation to treatment and diabetes control. Height, weight and body mass index (BMI) did not differ from those in a control group. The girls with diabetes increased their triceps and subscapular fat significantly despite a normal BMI. This increase in relation to control girls was most pronounced during late adolescence. Triceps skinfold and BMI after 5 years were both negatively correlated to insulin dose per kilogram body weight in the diabetic girls. We conclude that girls with diabetes accumulate subcutaneous fat in certain areas rapidly during adolescence in a completely different way from healthy girls.