This paper examines factors associated with the childhood obesity phenomenon in the U.S. A national longitudinal dataset “Early Childhood Longitudinal Study, Kindergarten-Fifth Grade” (ECLS-K) that has data for 12,719 children from fall 1998 (Kindergarten year) through spring 2004 (Fifth grade) is used. Two econometric models, a mixed-effects ordered Logit and a random-effects Tobit, are used to predict obesity status and the extent to which a child is overweight (the excess level of a child’s Body Mass Index). The results show that the more time parents spend working and certain non-parental care sources such as at-home childcare (as opposed to childcare at centers) are statistically significant in predicting the likelihood of childhood obesity and their level of excess weight. Endowment factors such as child’s birth weight and race, and other demographic factors such as parents’ social economic status, family structure, and family size are strongly correlated with these two outcomes. Environmental factors such as bed time, computer use, and physical education programs at school are negatively correlated with the level of excess weight but not statistically significant in predicting the probability of being overweight in children. The results of this study will be useful for educators, parents, and policy makers.