BACKGROUND: Obesity is a major public health problem. Studies have shown that there are racial and ethnic differences in the prevalence of obesity. However, there is limited research that examines the effects of sedentary and poor lifestyle behaviors and obesity among different racial and ethnic groups. Furthermore, most studies focus on the problem of obesity among children. This study was conducted to examine racial differences in determinants of obesity in adults in the United States. METHODS: Data from the 2005 Behavioral Risk Factor Surveillance System was used for this analysis. Demographics, lifestyle behaviors, and existence of chronic diseases were assessed. Data was stratified by race and multiple logistic regression analysis was conducted to examine determinants of obesity by race. RESULTS: The majority of the study participants (59%) were overweight or obese (BMI 22500). The following determinants were found to have a significant association with risk of obesity in whites, blacks and Hispanics: age, marital status, consumption of dietary recommendations of hits and vegetables, smoking status, and alcohol consumption. For whites, education and income level did not show a statistically significant association with obesity. For African Americans, sex, physical activity, and income levels did not have statistically significant associations with obesity. Income did show a statistically significant association with obesity in Hispanics.CONCLUSION: Overall, it was found that the determinants of obesity vary with ethnic groups. In order to effectively combat obesity, smoking cessation must also be paired with a healthy diet and regular exercise. In addition, interventions must be made in correlation with the needs of the community.