It is known that obesity is related to heart failure. Asymptomatic left ventricular diastolic dysfunction (LVDD) is associated with the development of heart failure. The relationship between subclinical LVDD and overweight in children is not clear. The purpose of this study was to evaluate the effect of body mass index (BMI) and waist circumference on left ventricular mass index (LVMI) and LVDD in overweight children.