Purpose We present a case of haemoperitoneum and haemorrhagic shock secondary to cholecystitis, with resultant rupture of a branch of the cystic artery, in the absence of a pseudoaneurysm. The patient was a middle-aged man who presented with severe right upper quadrant pain on a background of biliary colic. Imaging was consistent with cholecystitis, and significant volume free fluid in the right upper quadrant. The patient became shocked and was taken for laparoscopy, with conversion to laparotomy. 1.6 litres of haemoperitoneum was evacuated, and a cholecystectomy was performed. It appeared that a gallbladder perforation has caused rupture of a branch of the cystic artery, with resultant haemorrhage. No pseudoaneurysm was identified. Cholecystitis is a common surgical pathology, and this was a previously unreported, yet life-threatening complication of this pathology. This report aims to present a novel case and promote awareness of this dangerous complication. Methodology We reported a case of haemoperitoneum secondary to cholecystitis. We conducted a literature review to identify any previous cases of haemoperitoneum in the context of cholecystitis, and presented all relevant cases. Results No previous cases of this nature were found. Similar cases existed in the context of a cystic artery pseudoaneurysm; however no cases describe haemoperitoneum from cystic artery rupture without pseudoaneurysm. Conclusion We present a novel case with a potentially life-threatening complication of a common surgical pathology. This highlights the importance of early surgical exploration in deteriorating patients. We present a novel complication of cholecystitis, and a novel cause of haemoperitoneum.