The impact of central adiposity on left ventricular (LV) mass in childhood obesity has been little explored. This study evaluates whether central obesity influences LV mass and function in obese children.Biochemical, anthropometric and echocardiographic measurements were taken in obese (n=111, mean age 10.6+/-2.5 years) and non-obese children (n=30, mean age 10.8+/-3.0 years). Left ventricular function was analyzed by conventional and tissue Doppler echocardiography. LV mass was calculated according to the Penn convention and indexed for height(2.7) (LVM(i)). The obese group showed increased levels of LVM(i) as compared to the non-obese group (35.7+/-8.5 vs 23.5+/-2.8 g/h(2.7), p<0.0001). Among obese children, we observed a significant increase of LVM(i) across tertile of waist-height ratio (WHtR). The subjects identified by the highest tertile of WHtR, as compared to subjects identified by the lowest tertile, showed higher levels of BMI (29.5+/-5.4 vs 31.0+/-5.0 kg/m(2), p<0.0001) and LVM(i) (32.1+/-6.5 vs 37.1+/-8.5 g/h(2.7), p<0.01). Among obese children a positive correlation (standardized for age and gender) was found between LVM(i) and BMI (r=0.282, p<0.01) and WHtR (r=0.334, p<0.0001). To analyze the independent predictors of LVM(i), a stepwise linear regression analysis was performed using age, gender, BMI, blood pressure, heart rate, HOMA-IR and WHtR as independent variables. LVM(i) was independently associated only with WHtR (beta=0.309, t=3.238, p=0.002).Obese children show an increased LVM(i) and a preserved LV function. Central adiposity is the major determinant of left ventricular mass.