The quality of chest compression (CC) is influenced by the surface supporting the patient. The present study compared chest compression depth with and without a rigid backboard on an operating table with a pressure-distributing mattress. We hypothesized that the presence of a backboard would result in an increased depth of chest compression on the operating table with a pressure-distributing mattress. In a randomized crossover trial, we simulated in-hospital cardiac arrest in a Resusci Anne SkillReporter model placed on a standard operating table with a 6-cm-thick pressure-distributing mattress. A total of 25 male doctors performed CC 30 times, with or without the rigid backboard. Mean chest compression depth increased from 4.9 ± 0.4 to 5.4 ± 0.3 mm (P < 0.0001) when a backboard was present. Mean proportion of compressions >50 mm increased significantly with the presence of a backboard (53.6% ± 32.3%-81.8% ± 15.0%, P < 0.0001). Applying a backboard significantly increased CC depth during cardiopulmonary resuscitation of a manikin model on an operating table with a pressure-distributing mattress.