By 2050, the number of US older adults, defined as persons aged 65 and over, is expected to more than double, rising from 40.2 million to 88.5 million (1). Both aging and obesity contribute to increased health care service use (2, 3). Consequently, an increase in the proportion of older adults who are obese may compound health care spending. Given the demographic changes forecasted and the potential health care costs of obesity, it is important to track the prevalence of obesity among older adults (2, 3). This report presents the most recent national estimates of obesity in older adults, by sex, age, race and ethnicity, and educational attainment, and examines changes in the prevalence of obesity between 1999 and 2010.