A diaphragmatic injury is usually associated with injury to thoracic or abdominal organs due to blunt or penetrating trauma, and is uncommon after blast injury. We describe a patient with respiratory distress due to herniation of the stomach into the chest through a diaphragmatic injury, sustained 1 year previously when he suffered a blast injury while on deployed military operations, but without obvious visceral injury at that time. At emergency laparotomy there was a gastric perforation which was exteriorised as a gastrostomy and the diaphragmatic rupture closed. Postoperative pneumonia and pelvic abscess were both treated successfully and he left the hospital in good condition. Delayed treatment of traumatic diaphragmatic injury leads to an increased risk for herniation and/or strangulation of abdominal organs, which can be life-threatening. Recognising the symptoms indicating diaphragmatic injury is especially important in cases in which the relationship to previous trauma is less clear.