BACKGROUND AND OBJECTIVES: This study was aimed at evaluating the significance of blood pressure (BP) load in ambulatory blood pressure monitoring (ABPM) in obese children and adolescents. SUBJECTS AND METHODS: ABPM was conducted for 60 selected patients who had visited Sunlin Hospital between January 2008 and August 2008. Patients were classified into 3 groups; an obese group whose body mass index (BMI) was > the 95th percentile, an overweight group whose BMI was > the 85th percentile but less than the 95th percentile, and a normal group whose BMI was below the 85th percentile. Overall mean BP, day and night BP and BP load were measured by ABPM. RESULTS: Of the 60 patients, twenty-seven children belonged to the obese group, 9 and 24 to the overweight and the normal group, respectively. Among the three groups, the overall average systolic and diastolic BP, daytime diastolic BP, and systolic BP loads in daytime and nighttime were statistically different. Comparing the obese group with the normal group, systolic BP loads in daytime and nighttime in the obese group were significantly higher than those in the normal group. Also, the obese group had more patients whose BP loads were over 25% greater than the normal group while the difference in the number of patients with overall hypertension was not significantly different. CONCLUSION: Assessment of children's BP through assessment of BP load is a more detailed and precise tool than assessment through mean BP using ABPM and BP can be better controlled using measurement of BP load.