When performing cardiopulmonary resuscitation (CPR) on a patient with cardiopul-monary arrest in bed, it has often been recommended that a backboard be placed behind the patient. However, the effectiveness of the use of a backboard has not yet been adequately studied. As a result, there are differences in the criteria for the use of the backboard in the latest global guidelines. This study tested the usefulness of backboards on five different mattresses and the floor. The depth of manual chest compressions (MCC), the recoil of MCC, MCC success rate, and participant’s fatigue were evaluated with and without backboards. The MCC depth was maximum on the floor. On the bed, MCC depths were significantly deeper with backboards inserted than without backboards on all five mattress types. Similarly, MCC recoil depth and success rate, were more effective with the backboard inserted. It is recommended that MCC be performed on the floor only when manpower, environment, time and patient condition permit. However, if MCC must be performed on the bed, it is more effective with backboards placed behind a patient’s back on various types of mattresses.