While much of the industrialized world struggles for clues to the growing rise in obesity in their respective countries, researchers and service providers involved in understanding the health characteristics and health behaviors of persons with intellectual disability (ID) struggle with their own issues regarding the increased prevalence of obesity in this segment of the population. What is particularly alarming is that adults with ID residing in the United States in smaller, less supervised settings (e.g., group homes and family households) have a significantly higher rate of obesity compared to other countries and those living in larger and more supervised settings (e.g., institutions). These differences support the theory that the environment appears to exert a powerful influence on obesity in this population. Obesity presents a substantial threat to the livelihood of persons with ID and may have an effect on community participation, independent living, and healthy years of life. The lack of research on successful weight reduction strategies for obese persons with ID makes this an important and greatly needed area of research. © 2006 Wiley-Liss, Inc.