Objectives The recent prevalence rate of obesity in children is increasing, but so far the majority of ongoing research is focused on obesity in adults. Even comparison studies between obesity in adults and in children are insufficient at this stage. Thus, our research will investigate the characteristics of obesity in children based on the comparison with adults. Methods The blood levels including glucose, cholesterol, AST, ALT of obese children and obese adults were compared and analyzed. Results From comparison studies, the levels of glucose, cholesterol, ALT in adults were higher than in children. In order to take account the age differences, only the rate of abnormal levels based on the reference range were compared. As a result, the abnormal rate in blood cholesterol level was higher in children. Conclusions Childhood obesity may develop complications at early age and has high potential risk to result in adult obesity as well. Therefore, child obesity needs to be treated with more caution and careful attention.