Obesity and related health complications are a growing worldwide problem among all age groups - children, adolescents, and adults. Obesity is the second most preventable cause of disease and death in the world today. Obesity is strongly associated with metabolic syndrome, a cluster of endogenous risk factors that increase the risk of developing both cardiovascular disease and diabetes. The U.S. has historically had the highest prevalence of overweight in the world. However, at the turn of the millennium, rates of overweight in Mexico were similar to those in the U.S. Moreover, in the U.S., populations of Mexican origin or descent are at elevated risk of obesity and related disorders. Obesity is the result of a complex set of factors that operate at multiple levels of the ecology (e.g., genetic predispositions, lifestyle factors, psychosocial conditions). As a result, multidisciplinary investigations are needed to understand the origins of obesity and associations between obesity and a range of health-related outcomes. This symposium brings together researchers who are investigating obesity and metabolic syndrome among Mexican-origin populations from a range of disciplinary perspectives.