BACKGROUND: Citizen responder programs are implemented worldwide to dispatch volunteer citizens to participate in outofhospital cardiac arrest resuscitation. However, the risk of injuries in relation to activation is largely unknown. We aimed to assess the risk of physical injury for dispatched citizen responders. METHODS AND RESULTS: Since September 2017, citizen responders have been activated through a smartphone application when located close to a suspected cardiac arrest in the Capital Region of Denmark. A survey was sent to all activated citizen responders, including a specific question about risk of acquiring an injury during activation. We included all surveys from September 1, 2017, to May 15, 2020. From May 15, 2019, to May 15, 2020, we followed up on all survey nonresponders by phone call, e-mail, or text messages to examine if nonresponders were at higher risk of severe or fatal injuries. In 1665 suspected out-of-hospital cardiac arrests, 9574 citizen responders were dispatched and 76.6% (7334) answered the question regarding physical injury. No injury was reported by 99.3% (7281) of the responders. Being at risk of physical injury was reported by 0.3% (24), whereas 0.4% (26) reported an injury (25 minor injuries and 1 severe injury [ankle fracture]). When following up on nonresponders (2472), we reached 99.1% (2449). No one reported acquired injuries, and only 1 reported being at risk of injury. CONCLUSIONS: We found low risk of physical injury reported by volunteer citizen responders dispatched to out-of-hospital cardiac arrest. Risk of injury should be considered and monitored as a safety measure in citizen responder programs.