Out-of-hospital cardiac arrest (OHCA) mortality remains high. The best survival rates are achieved when trained people provide OHCA victims with cardiopulmonary resuscitation (CPR); however, it is estimated that only 25% of victims receive CPR. This community health study aims to evaluate the effectiveness of a training programme in basic CPR and in the use of an automatic external defibrillator (AED) on knowledge and skills for lay people, and its social impact. The training courses were based on Catalan Council of Resuscitation guidelines. Data were collected on sociodemographic characteristics, evaluation of knowledge and practical skills at baseline and at the end of the training courses, and also on the social impact of the programme. A total of 36 training courses with 482 participants were carried out, and most participants achieved a qualification of suitable. The mean score in knowledge was 3.1 ± 1.1 at baseline and 3.8 ± 1.2 (p = 0.001) at the end of the programme. Participants rated the training courses as very satisfactory, considered the training useful, and felt more qualified to respond to an emergency. This study shows that a high percentage of participants acquired skills in basic CPR and use of an AED, which confirms the usefulness and effectiveness of training courses and its important social impact.