The clinical periodontal status of 44 insulin-dependent diabetic children and adolescents and 20 healthy control subjects was compared for a period of approximately 5 years. Fasting blood glucose, fructosamine, and glycosylated hemoglobin (HbA1) values were determined at baseline and 5 years later. The differences in the clinical and laboratory parameters were compared during the study period. The differences between the two groups were also evaluated. The only statistically significant difference observed in the diabetic group was clinical attachment loss (CAL). The CAL was statistically significantly higher in the diabetic group compared to the controls, and a statistically significantly higher in the diabetic group compared to the controls, and a statistically significant positive correlation was observed between the duration of diabetes and CAL. Fructosamine was also correlated with the gingival index in the diabetic group while there was no correlation in the controls. It may be concluded that diabetes modifies the clinical status of the periodontal tissues and increases clinical attachment loss.