Sarcina ventriculi is an increasingly common bacterium with a variable pathogenic role. It is often an incidental finding in asymptomatic patients but can also lead to life-threatening conditions, such as gastric perforation and emphysematous gastritis. We report a case of a 14-year-old boy with fatal emphysematous gastritis caused by S. ventriculi, who presented with abdominal pain and vomiting. His medical history included infantile left hemiparesis and operation of patent ductus arteriosus. Emergency surgery was scheduled due to the extremely dilated stomach and gastric pneumatosis, and a total gastrectomy was performed. On the third postoperative day, he suddenly dies, and the diagnosis was confirmed postmortem. This case is an opportunity to review the clinical presentation of emphysematous gastritis and to point out the role of the histopathological examination for the identification of the bacteria.