Diastolic functions of the heart, measured by pulsed tissue Doppler echocardiography from 25 overweight and obese children, were compared with 91 children of normal weight who were 10 to 18 years old and had normal 2-dimensional echocardiographic examinations. Overweight and obese subjects, as compared with the control group, had a significant decrease in the peak early diastolic E wave at the ventricular septum (12.8 ± 2.1 vs 13.8 ± 1.8, p = 0.025) and a significant increase in the late diastolic A wave at the ventricular septum (7.3 ± 1.8 vs 6.4 ± 1.4, p = 0.016), lateral wall (7.8 ± 4.3 vs 6.4 ± 2.7, p = 0.000), and posterior wall (4.2 ± 1.7 vs 3.6 ± 0.9, p = 0.041). In addition, the overweight children had a significantly lower E/A ratio at the septum that was inversely related to body mass index.