The recent decision by the Centers for Medicare and Medicaid Services to expand the indications for cardiac rehabilitation (CR) provides an opportunity to review the clinical evidence of the efficacy of exercise in the CR setting for patients who have experienced an acute myocardial infarction, coronary artery bypass graft surgery, stable angina, percutaneous coronary intervention, chronic heart failure, cardiac transplant, or cardiac valve repair/replacement. Evidence shows that physician-directed, exercise-based CR positively affects the basic pathophysiology of coronary artery disease, the extent of disability and level of quality of life, and the ability to potentially impact events of both morbidity and mortality. The role of CR, including regular exercise, lifestyle modification, and appropriate medical therapy, is effective in younger and older men and women with cardiac diagnoses. The efficacy of this important therapeutic modality warrants its more widespread application.