We assessed the prevalence of high body mass index (BMI) in a large cohort of military children. We compared BMI data from electronic medical records of military children aged 2 to 18 years with BMI data from the National Health and Nutrition Examination Survey (NHANES). The 23,778 military children studied were significantly less likely than the NHANES children to be overweight (27.1% vs 31.8%) or obese (11.9% vs 16.9%). Even though military parents are required to maintain fitness and weight standards, the absolute difference between military and civilian children was small.