Although the benefits of cardiac rehabilitation programs are well established, it is important to address potential medical hazards to determine the risk-benefit ratio of these programs. Cardiac arrests, acute myocardial infarctions, and deaths related to exercise sessions are the cardiovascular complications of greatest importance. National studies have documented a low incidence of these complications in supervised, outpatient programs. Studies have also identified clinical characteristics of the “high-risk” cardiac rehabilitation participant. To maintain high levels of safety in cardiac rehabilitation programs, it is important to continue the high standards of cardiac rehabilitation, particularly in the areas of medical screening and assessment, patient education, patient supervision, and emergency treatment.