Introduction: Hyperbaric pressure is a condition of environmental pressure that is greater than 1 atmosphere experienced by divers. Hyperbaric pressure can damage the teeth, as well as restorations. The use of fiber posts in post-endodontic restorations has limitations in adapting the shape of the post to the root canal which can cause the thicker of resin cement so that the risk of void formation will be greater. This study aims to evaluate the effect of hyperbaric pressure on fracture resistance and fracture patterns in different post systems.