Nationwide data on obesity prevalence in American Indian communities are limited. We describe the body composition and anthropometric characteristics of schoolchildren from 7 American Indian communities enrolled in the Pathways study, a randomized field trial evaluating a program for the primary prevention of obesity. A total of 1704 children in 41 schools were enrolled in the study. Basic anthropometric measurements included weight, height, and triceps and subscapular skinfold thicknesses. Percentage body fat was estimated from bioelectrical impedance and anthropometric variables with the use of an equation developed and validated for this population. The children's mean (+/- SD) age was 7.6 +/- 0.6 y, and their mean weight and height were 32.1 +/- 8.9 kg and 129.8 +/- 6.3 cm, respectively. Mean body mass index (BMI; in kg/m(2)) was 18.8 +/- 3.9, and mean percentage body fat was 32.6 +/- 6.8%. With the use of current Centers for Disease Control and Prevention reference values, 30.5% of girls and 26.8% of boys were above the 95th percentiles for BMI-for-age, and 21% of girls and 19.6% of boys were between the 85th and 95th percentiles. Although there was a wide range in BMI across study sites and for both sexes, the percentage of children with a BMI above the 95th percentile was consistently higher than the national averages in all communities studied and in both girls and boys. Overweight can be documented in a substantial number of American Indian children by the time they reach elementary school. Despite differences in the prevalence of overweight observed among communities, rates are uniformly high relative to national all-race averages.