The objective was to determine how the prevalence of obesity among children in pediatric practices in South Carolina varied from national data. Children were sampled from the South Carolina Pediatric Practice Research Network (SCPPRN) using measured weight and height, and these data were compared with national data. Children were categorized as obese if their BMI exceeded the 95th percentile. Age was stratified according to national data (2-5 years, 6-11 years, and 12-19 years). Comparisons were made by age, gender, and race/ethnicity. The prevalence of obese children in the SCPPRN aged 2 to 5 years was 14%, 6 to 11 years was 21.7%, and 12 to 19 years was 17.3%. National comparison rates were 13.9%, 18.8%, and 17.4%, respectively. Gender and racial disparity were present, with black boys and white girls having a high prevalence of obesity early in life, which decreased in adolescence. Black girls had the opposite course. Obesity prevalence varied among practices, from 7.5% to 26.9%.