In 1993 and 1994, a questionnaire survey was conducted on elementary school students of fourth and fifth grades living in Shengyang city (620 children), China and in Okayama city (579 children), Japan to determine defferences in the degree of obesity and life styles between the children of the two countries. Children whose body mass index (BMI) was 22 or higher were considered obese. The percentate of obese children was 5.7 in Shengyang and 5.4 in Okayama. Multiple logistic regression analysis of dietary patterns and life styles to explain childhood obesity in both countries showed the importance of consuming large amounts of grain products, potatoes, sugar, and oily foods as factors related to chilihood obesity. Physical activity has also been shown to be negatively and significantly associated with childhood obesity. Daily intake of enetgy, carbohydrate, and fat among obese children was significantly greater than those among nonobese children. The length of time spent watching television among the Japanese children was found to contribute to childhood obesity.