Diabetes is associated with a variety of adverse health conditions including cardiovascular morbidity and mortality. Sedentary activity is a primary contributor to the rapidly escalating prevalence of prediabetes and diabetes in the United States, and a majority of US adults are not meeting recommended guidelines for exercise. This chapter reviews the available research regarding the influence of daily lifestyle activity and structured exercise on health improvement for persons with diabetes. A number of behavioral prescription recommendations are derived from this literature, and the benefit of utilizing behavioral modification techniques in the development and maintenance of increased exercise efforts is discussed. Examples for using specific behavioral techniques in exercise are provided and environmental challenges to creating large-scale behavioral interventions to promote increases in the public’s activity level are reviewed.