Abstract: This study was to evaluate the left ventricular mass index (LVMI) and geometry in obese children. Forty-nine obese children, median age of 9.7 (range 3.4-15.4 years), underwent echocardiography to assess LVMI and Relative Wall Thickness (RWT). LV geometry was categorized as normal, concentric remodeling, eccentric hypertrophy and concentric hypertrophy. Mean weight was 61.8 ±22.0 kg, BMI 29.9 ±5.8 kg m-2, LVMI 38.3 ±8.9 g m-2.7 and percentage of actual weight to ideal body weight-for-height (IBW %) 172.4 ±28.3%. Twenty-one children had mild to moderate obesity (group 1) and 28 had severe obesity (group 2). Twenty-six children had normal LV geometry, 2 had concentric remodeling, 15 had eccentric hypertrophy and 6 had concentric hypertrophy. LVMI and abnormal geometry in group 2 were significantly greater than in group 1 (40.7 ±8.8 vs 35.1 ±8.1 g m-2.7, 60.7 vs 28.6%, p = 0.03). Thirty-seven children (75.5%) had normotensive whereas 12 (24.5%) had systemic hypertension. The LVMI and abnormal geometry were not significantly different in both groups (37.6 ±9.7 vs 40.4 ±5.7 g m-2.7, 40.5 vs 60.7%). Left ventricular mass and abnormal LV geometry were increased in obese children especially in severe obesity. These may increase cardiovascular risk in the future. Weight control to decrease the severity of obesity should be recommended.