This review provides a summary of treatment of cardiac arrest with mechanical cardiopulmonary resuscitation (CPR). CPR provides chest compressions according to guidelines in the treatment of out-of-hospital cardiac arrest. This is useful in situations where CPR cannot be safely delivered (e.g. during transportation and prolonged CPR). Randomized controlled trials have not shown improved patient outcomes after treatment with mechanical CPR compared to manual CPR. Mechanical CPR can, like manual CPR, cause injuries, and some may be life-threatening. Mechanical CPR is therefore recommended as an adjunct to manual CPR in special circumstances but not used routinely.