Background: Pacific Islander, Asian, and mixed-ethnicity children are not described in national nutrition and health surveys. Methods: Data on BMI values of 4608 5-to 8-year-old children available from Kaiser Permanente Hawaii electronic medical records in 2010 were analyzed for prevalence of overweight and obesity and for ethnic differences in BMI and risk for overweight and obesity, controlling for age, sex, neighborhood education level, and on a subset (n = 2169) that further controlled for maternal education and maternal age. Kaiser Permanente data allow for reporting of multiple ethnicities.Results: Data revealed that 33% of this child population was of mixed ethnic ancestry. Prevalence of overweight and obesity was 32.6% (12.9% overweight and 19.7% obese). However, Samoan children and children of Native Hawaiian, Filipino, and mixed ethnic ancestries had higher levels of overweight and obesity than whites or Asians. Higher neighborhood education level, higher maternal education level, and older maternal age were associated with decreased risk of overweight and obesity, except for children whose mothers were between 21 and 30 years old, who had a higher risk for obesity than those whose mothers were under 20 years of age (odds ratio = 1.34).Conclusions: Populations of mixed ethnicities in the Pacific region deserve further study related to healthy body size and acculturation to environment and lifestyle.