Objective: The purpose of this study is to determine specific risk factors associated with obesity among African American, Hispanic and Caucasian children. Design: This is a cross-sectional study conducted on 1076 fifth grade children from 17 elementary schools at Fort Worth, Texas. Data were collected through questionnaires and physical assessments performed at schools. Crude and adjusted odds ratios were determined for the risk factors of obesity in each ethnic group. Results: More African American (32.8 per cent) and Hispanic (31.9 per cent) children were overweight compared to Caucasians (23.5 per cent). A specific risk factor seen in the African American children was the frequent use of sweets and sugar-sweetened drinks, which increased the odds of obesity nearly three-fold. In the Caucasian children, the odds of obesity increased over two-fold as a result of frequent consumption of snacks with a high fat content. In Hispanic children, specific risk factors included physical inactivity and frequent consumption of multiple servings of fruit, which increased the odds of obesity approximately two-fold and 68 per cent, respectively. Although eating more fruits is usually considered a healthy behaviour, excessive fruit consumption appears to increase the likelihood of obesity among Hispanic children in this sample. Conclusion: Risk factors associated with obesity are different in children of different ethnic backgrounds. Knowledge of these differences in risk factors may help design better targeted prevention approaches. © SAGE 2008.