Physical inactivity is a major public health problem of the 21st century. The spiraling cost of a sedentary lifestyle on morbidity and mortality isn’t just dramatic, it is devastating, with an estimated 250,000 premature deaths annually in the U.S. These deaths are directly a function of physical inactivity, which constitutes the 4th leading cause of death globally (with about 3.3. million attributable deaths per year). Exercise medicine serves as a resource for physicians and other healthcare professionals, while providing the unique opportunity for Board Certified Exercise Physiologists to further establish themselves as advocates of the benefits of exercise medicine, physiological assessments, and the exercise prescription. This chapter makes the connection between the benefit of regular exercise on both the primary and secondary prevention of coronary heart disease, obesity, type 2 diabetes, low back pain, hypertension, breast and colon cancer, depression, dementia, and osteoporosis. Without a doubt, exercise is medicine that should be prescribed by Board Certified Exercise Physiologists.