Background: The cardiovascular disease was the main cause of death throughout the world. The first aid that should be taken by the first responder or witness was an important part in the chain of survival out of the hospital that could improve the prognosis and avoid the rest of the symptoms. Hence, it is important for common people to know and possess the skill, especially the cardiopulmonary resuscitation, to handle the emergency situation. Schools became the appropriate place to organize the first-aid training because the students were more conditioned in emotional, social and cultural terms.Methods: This study utilized the quasi-experiment method. The total number of subjects was 124 students who studied in Kalibawang 1st State Senior High School, and in Samigaluh 1st State Senior High School, both of them school is located in Kulon Progo district, Indonesia. The subjects were divided into three groups using three different methods, namely lecturing-discussion, poster demonstration, and audio-visual media.Results: The pre-test and post-test results showed that there was a knowledge improvement after the training using the lecturing (p=0.000), poster (p=0.000) and audio-visual methods (p=0.000). The cardiopulmonary resuscitation skills in the lecturing (p=0.000), poster (p=0.000) and audio-visual methods (p=0.000) groups showed the improvement after the first-aid training in school.Conclusions: This study proved that the first-aid training in the school gave effect on the improvement of the knowledge and skill in handling the emergency situation, particularly the cardiac arrest through cardiopulmonary resuscitation.