Rescue breathing performed too vigorously or by untrained individuals may cause gastric distension and perforation. A 26-year-old woman is presented who developed acute abdominal pain and distension after receiving rescue breathing following a heroin overdose. Massive pneumoperitoneum was seen on chest x-ray, and on subsequent laparotomy, a 4cm laceration was found in the lesser curvature of the stomach. Review of the literature suggests that the lesser curvature is particularly susceptible to perforation following over-distension. Emergency personnel should be aware of this rare, but serious, complication. Expansion of community and first responder naloxone use in the proper clinical setting may further diminish utilization of rescue breathing. Butterfield M , Peredy T . On-scene rescue breathing resulting in gastric perforation and massive pneumoperitoneum. Prehosp Disaster Med. 2017;32(6):682-683.