Acquired diaphragmatic hernias are usually posttraumatic in occurrence. In patients who have blunt trauma and associated diaphragmatic hernia, the diagnosis may be missed or delayed, often leading to poor treatment outcomes. We present a rare occurrence of tension viscerothorax due to missed traumatic diaphragmatic rupture in a 25-year-old woman whose condition was complicated by gangrene and perforation of the fundus as well as questionable viability of the anterior wall of the body of the stomach. The patient had a successful emergency transabdominal suture plication of the diaphragm and gastroplasty and has remained symptomless 3 months postoperatively.