Adaptive behavior consists of the social, conceptual and practical skills an individual must execute to function independently in their everyday life. Individuals with Down syndrome have limitations in their adaptive behavior due to cognitive and physical deficits. The aim of this study was to examine if an exercise program would improve the adaptive behavior skills in persons with Down syndrome. The exercise intervention, Exercise for Adults with Down Syndrome (ExDS), was a semester long program where adults with Down syndrome participate in twice weekly workouts planned and executed by Arizona State University students. The workouts consisted of an aerobic warm up, aerobic exercises, resistance exercises, balance exercises and stretches. The participants' adaptive behavior and cognitive planning ability were assessed before ExDS and after ExDS. The Adaptive Behavior Assessment System Second Edition (ABAS-II) was used to measure adaptive behavior. The ABAS-II consisted of a forum that addressed the Social, Conceptual and Practical domains of adaptive behavior and was filled out by the participants' caregiver. The Tower of London (ToL) was used to measure cognitive planning ability. The change in the ABAS-II scores from pre- to post-testing were statistically insignificant. The change from pre- to post-testing in the ToL scores approached statistical significance. Limitations included bias caregiver perception and respondent inconsistency. There is a need for further research on the effect of exercise on the adaptive behavior in adults with Down syndrome.