Immediate provision of cardiopulmonary resuscitation (CPR) by a layperson or a health care provider may double an individual’s likelihood of surviving cardiac arrest. Despite extensive CPR training programs throughout the United States, studies from a range of communities have demonstrated that fewer than one-third of individuals who experience out-of-hospital cardiac arrest receive bystander-initiated CPR before the arrival of emergency medical services personnel and that CPR delivery varies considerably between different locales.1,2 Whether such variability is the result of differences in a willingness to provide care or differences in the prevalence of CPR training remains unknown. This knowledge gap underscores a related and perhaps more fundamental question that remains unanswered some 50 years after the development of CPR: What is the rate of CPR training in the US population?