To evaluate the role of obesity and nutrient intake on serum IGF-1 and serotonin levels in 80 elementary school children (aged 10. 8 yr, 47 boys, 33 girls), we investigated the anthropometric data and the nutrient intake by questionnaries including food daily record, and measured serum IGF-1 and serotonin using RIA and HPLC F-1050 respectively. We obtained the following results by obesity index (underweight-, normal-, obese group). The protein intake of normal group was higher than the others (p < 0.05). The underweight and obese groups had snacks more often than the normal group. The obese group preferred‘cookies’and‘fries’more than the other groups. The serum serotonin levels showed weak correlation with fat (r = 0.315, p < 0.01), fiber (${gamma}$ = 0.280, p < 0.05) and energy intake (r = 0.242, p < 0.05), but no differences in anthropometric data by obesity index. The serum IGF-1 level was significantly correlated height (r = 0.649, p < 0.001), weight (r = 0.437, p < 0.001) and hip (r = 0.417, p < 0.001), but showed weak correlation with energy intake (r = 0.232, p < 0.05) and carbohydrate intake (r = 0.244, p < 0.05). In this study, we could see only partly correlation among the serum IGF-1 and serotonin and obesity and nutrient intake. Forker research is required into consideration of the essential role of these hormones during a growth period.