The number of older adults with intellectual and developmental disabilities (IDD) has increased rapidly in the United States as part of the general "graying"of the country. This has presented challenges in maintaining the quality of life and health for these individuals in later years. Issues including diagnostic overshadowing (the tendency to overlook symptoms of mental or physical illness as causes for decline), lack of knowledge about aging in adults with IDD, and health care disparities are discussed in this article along with recommendations for clinicians to help them meet this growing challenge.