Purpose: The purpose of this paper is to investigate the effects of the intervention of low-dose, high-frequency cardiopulmonary resuscitation (CPR) training with feedback for firefighters for one month. Design/methodology/approach: The study had a quantitative approach. Data were collected through an intervention by means of simulation. The data collection consisted of a pre- and post-assessment of 38 firefighter’s CPR performance. Findings: There was a statistically significant improvement from pre- to post-assessment regarding participants’ compression rates. Compression depth increased statistically significantly to average 2 mm too deep in the group. Recoil decreased in the group with an average of 1 mm for the better. There was a statistically significant improvement in participants’ ventilation volume from pre- to post-assessment. Originality/value: Prehospital staff such as firefighters, police, and ambulance perform CPR under less than optimal circumstances. It is therefore of the utmost importance that these professionals are trained in the best possible way. The result of this study shows that low-dose, high-frequency CPR training with an average of six training sessions per month improves ventilation volume, compression depth, rate, and recoil. This study concludes that objective feedback during training enhances the firefighters’ CPR skills which in turn also could be applied to police and ambulance CPR training.