PURPOSE: Body mass index(BMI), skinfold thickness and arm circumference are commonly used to evaluate obesity in children. There is a need for new standards of these items on Korean children. We performed this study to provide up-to-date reference percentile values and percentile charts for these three items. METHODS: Standardized measurements of height, weight, skinfold thickness(triceps, subscapular) and arm circumference on a total of 31,188 infants and children from age 1 to 18 years during January to December 1998 were used to calculate percentile values and to develop smoothed percentile charts. RESULTS: The mean BMI increased with age and showed similar values in both sexes, but 95th percentile values were slightly higher for boys than girls. The percentile values of BMI were consistently higher than those reported previously in Korea, particularly for the 95th percetile values. Triceps and subscapular skinfold thickness showed significant increase compared with previous studies and significantly higher for females than males. Arm circumference also showed significant increase compared with the previous studies. It was significantly higher for males than females. BMI was more closely related with arm circumference than skinfold thickness. CONCLUSION: The percentile values and percentile charts of BMI, skinfold thickness and arm circumference will allow pediatricians to evaluate obesity in Korean children.