The annual Hajj (pilgrimage) to the Islamic holy shrines at the city of Makkah in the Kingdom of Saudi Arabia is one of the largest yearly recurring mass gatherings worldwide. We aim to evaluate the outcome of outside and inside the hospital cardiopulmonary resuscitation to resuscitate cardiopulmonary arrest among pilgrims. In a prospective cohort study of cardiac arrest patients during Hajj period (January 2004–December 2007 and January 2010–December 2011), 426 patients were resuscitated. The mean age was 64.0 ± 12.0 years. A total of 252 (52.2%) patients had an outside the hospital cardiac arrest, whereas 174 (40.8%) patients had an inside the hospital cardiac arrest. The survival rate of outside the hospital was 5%, whereas inside the hospital was 30%. The overall survival rate was 15.5%. During Hajj, cardiopulmonary resuscitation inside the hospital was associated with better clinical outcomes than outside the hospital. Patients with cardiac arrest outside of the hospital are much less likely to survive due to the lack of immediately trained help and the delay of arrival of aid due to overcrowding. Sudden cardiac arrest leading to death could be minimized if cardiopulmonary resuscitation and defibrillation are delivered before the arrival of emergency medical services.