Vascular aging is a chronic process, and many negative effects of obesity in this process have been well defined. We assessed arterial stiffness in obese adolescents and evaluated the relationship between intra-abdominal fat distribution and arterial stiffness. Arterial stiffness parameters and pulse wave velocity (PWV) were evaluated in 61 obese adolescents and 58 healthy controls. Carotid-femoral PWV was calculated by arterial tonometry. Additionally, all obese children were evaluated for metabolic syndrome and insulin resistance. Intra-abdominal fat distribution, including subcutaneous, preperitoneal and visceral fat thicknesses, was assessed by ultrasonography. PWVs of obese children were significantly higher than those of healthy controls (5.0 +/- 0.7 m/s vs. 4.7 +/- 0.5 m/s). Parameters affecting PWV were evaluated by regression analysis. The independent variable in the regression analysis model was PWV, and the dependent variables were age, metabolic syndrome, body mass index and Homeostasis Model Assessment-Insulin Resistance, as well as subcutaneous, preperitoneal and visceral fat tissue thicknesses measured by ultrasonography. The only parameter associated with PWV was preperitoneal fat tissue thickness. Vascular changes related to obesity may begin in adolescence, as illustrated by the increased PWV. Preperitoneal fat tissue may be related to arterial stiffness. Intra-abdominal fat distributions obtained by ultrasonography may provide clinicians with valuable information needed to determine cardiovascular disease risk factors in obese adolescents. (E-mail: firstname.lastname@example.org) (C) 2014 World Federation for Ultrasound in Medicine & Biology.