OBJECTIVE: To determine if children with type 1 diabetes have increased arterial stiffness by estimating augmentation index with the simple noninvasive technique of radial artery tonometry. RESEARCH DESIGN AND METHODS: We studied 98 type 1 diabetic children and 57 healthy control subjects, ages 10-18 years, matched for age, sex, race, and BMI, generating 43 matched pairs. Radial artery tonometry was performed, and blood was collected for analysis of fasting lipids, HbA1c, glucose, and cytokines in all children. RESULTS: Children with diabetes had a significantly higher augmentation index corrected to a heart rate of 75 (AI75) than their matched control subjects. Mean AI75 in type 1 diabetic subjects was 1.11 +/- 10.15 versus -3.32 +/- 10.36 in control subjects. The case-control difference was 5.20 +/- 11.02 (P=0.0031). CONCLUSIONS: Children with type 1 diabetes have increased arterial stiffness compared with healthy control subjects. Radial artery tonometry is a simple noninvasive technique that could be added to the armamentarium of tests used to provide cardiovascular risk stratification in children with type 1 diabetes.