The purpose of this study was to evaluate the energy intake and energy expenditure of obese children. The body weight and height were measured, and the daily energy intake and activity pattern assessed for one day, using the 24 hour recall method and interviews in 83 elementary school children (59 boys and 24 girls). The average age, height, weight, ideal body weight and obesity index in boys and girls were 11.8 years, 144.8 cm, 54.2 kg, 39.9 kg and 35.9% and 11.5 years, 140.8 cm, 48.9 kg, 36.9 kg and 33.7%, respectively. The mean daily energy intakes of boys and girls were 1,670.5 and 1,656.5 kcal; these being 76.4 and 88.5% of estimated energy requirement for Koreans, respectively. The energy intake ratio from carbohydrates, proteins and fats in boys and girls were 61.5:14.7:23.6 and 62.0:14.7:23.7, respectively. The resting energy expenditure, as estimated by the Harris-Benedict, WHO/NAO/FAO and Korean DRI formulae in boys and girls were 1,452.7, 1,239.2 and 1,629.2 kcal and 1,323.9, 1,156.0 and 1,252.4 kcal, respectively. The activity coefficient for both the boys and girls was 1.39. The daily energy expenditure of boys (1,990.7 kcal) was significantly higher than that of girls (1712.1 kcal). No significant correlations were found between the obesity index, energy intake and energy expenditure. These results suggested that a nutrition and exercise program is required to increase the energy expenditure of elementary school children. Further research will be needed to assess multiple dietary factors and dove]lop a standard method for assessing the energy expenditure of obese children.