The study objective was to establish the range of body-composition values for a multiethnic female population (aged 3-18 y) by using dual-energy X-ray absorptiometry (DXA). Results for 313 females in three ethnic groups [European American (white), n = 141; African American (black), n = 104; and Mexican American (Hispanic), n = 68] are reported. Changes in the bone mineral content (BMC), lean tissue mass (LTM), fat mass, and percentage fat are presented as functions of age. Analysis of variance with age, weight, and height as covariates was used to evaluate differences among the three ethnic groups. BMC and LTM were higher in the black than the white females, but no significant difference in BMC or LTM was evident between the white and Hispanic groups. The relation between the BMC and LTM compartments was linear (r = 0.963, P < 0.0005) and independent of age or ethnic classification. The Hispanic and black females had higher percentage fat values than the white group. When adjusted for body size, the Hispanic females continued to have significantly higher fat mass and percentage fat than the white females in this study. Ethnic-specific equations for body composition as a function of age, weight, and height are given. In addition, the results for the white females in the present study were compared with DXA-derived body-composition data for reference populations in other countries. We conclude that reference values of total body composition for young females need to be ethnic-specific.