In recent years, there has been a growing concern as to the importance of exercise in the holistic management of individuals with Down syndrome (DS). In fact, several studies have reported that regular exercise may improve the health of these individuals, since it may help reduce obesity, insulin resistance and oxidative damage, among other problems. Similarly, exercise may improve the quality of life of individuals with DS by promoting their functional independence as well as their social integration in the workplace, since most of their jobs are based on physical tasks. In addition, an increasing number of sport events are being organised all over the world for individuals with DS by national federations and international institutions, such as the Special Olympics and International Paralympics Committee. In this regard, improving the physical performance of high performance athletes with mental retardation also requires specialised attention from a multidisciplinary team.Fortunately, anthropometric assessment, including body composition and somatotype analysis, may help these professionals not only achieve all these goals, but also achieve them safely. It should also be noted that this assessment is inexpensive, easy to perform and non-invasive. However, anthropometric assessment is not widely used by professionals in their daily practice to date, which may be explained, at least in part, by the dearth of available information in the literature.Consequently, this chapter has been written to provide an update on this topic for healthcare providers and sport-related professionals who work with individuals with DS.