Adiposity rebound (AR) is used as an indicator to predict obesity in adults. Previous studies about AR in the U.S. were based on local data; therefore, the generalizability of study results is limited. The purpose of this study was to identify the timing of AR for U.S. children using a national survey data set, the National Health and Nutrition Examination Survey (NHANES). Combined data of NHANES 1999-2008 were used to estimate the national level of this critical period for U.S. children developing obesity. Data of 8813 children 2 to 10 years of age were analyzed. Mean body mass index was estimated using the survey sample analysis method. Visual inspection method was employed to examine the timing of AR. Gender and race/ethnicity differences in AR were identified at an early age. AR occurred earlier in girls and in Non-Hispanic African-American children than in Non-Hispanic Caucasian children. Differences in timing for AR by gender and race/ethnicity should be considered in planning early and timely intervention efforts to prevent childhood obesity.