This study surveyed 146 obese elementary school children(94 male and 52 female) in Seoul, and measured height, body weight, degree of obesity, blood pressure, fasting blood sugar, serum lipid profiles and liver function. The hypertension was above 95 percentile depending on age and sex. and the hyperglycemia was defined as above 110mg/dl. The hypercholesterolemia and hypertriglyceridemia were defined as above 200mg/dl, 160mg/dl, repectively. The abnormal liver function was considered as elevated alanine aminotransferase(ALT>35IU/L)or aspartate aminotransferase(AST>35IU/L). The results were as follows: 1. The mean degree of obesity was $29.56pm12.56\%$, and the percentage of overweight was $18.5\%$, mild obesity $41.1\%$, moderate obesity $35.6\%$, severe obesity $4.8\%$ respectively in surveyed children. 2. The systolic blood pressure was $108.34pm13.73mmHg$, diastolic blood pressure was $67.46pm8.27mmHg$. 3. FBS was $93.79pm6.51mg/dl$. 4. Total cholesterol, triglyceride, ALT and AST were $183.34pm31.38mg/dl$. $115.55pm56.43mg/dl,;24.08pm18.42IU/L,; 28.73pm10.45IU/L,$ respectively. 5. The prevalence of complications was $47.2\%$ : hypertension$(13\%)$, hyperglycemia$(0.7\%)$, hypercholesterolemia$(23.3\%)$, hypertriglyceridemia$(17.1\%)$, and liver dysfunction$(21.9\%)$. In conclusion. childhood obesity is associated with various risk factors. Therefore, the aggressive approaches to successful prevention, early detection, and effective treatment of obesity in children are urgently required.