To examine the prevalence of overweight, obesity, and extreme obesity in a predominantly minority group of adults with disabilities.Cross-sectional study using secondary data analysis.Major university medical center.Adults with physical and cognitive disabilities (N = 306).Not applicable.Direct measures of height and weight to classify subjects into 3 obesity categories: overweight (body mass index [BMI] range, 25-29.9 kg/m2), obese (BMI range, 30-39.9 kg/m2), and extreme obesity (BMI, > or = 40 kg/m2).People with disabilities, regardless of sex, race and ethnicity, or age, had significantly higher rates of overweight, obesity, and extreme obesity compared with people without disabilities. Extreme obesity (BMI, > or = 40 kg/m2) was approximately 4 times higher among people with disabilities than in the general population (odds ratio = 4.08; 95% confidence interval, 3.50-4.66). There were also substantial differences in obesity prevalence among people with disabilities, using actual measurement data, compared with self-reported data from previously published data sets.The disparity in excess body weight between people with and without disabilities, particularly in the category of extreme obesity, along with substantial differences in obesity prevalence between actual and self-reported data, show a critical need to better understand why these differences exist.