Abstract 1. 1. A total of 249 cases of acute perforation of a duodenal ulcer occurring at the Genesee and Strong Memorial Hospitals are reviewed. 2. 2. Major sequelae developed in 65.1 per cent of 167 cases followed. 3. 3. In 27.5 per cent of the 109 cases with major sequelae the symptoms recurred within six months of closure. 4. 4. Definitive surgery became necessary in 36.5 per cent of the 167 cases followed. 5. 5. Additional procedures to simple closure of the perforation exclusive of gastric resection did not reduce the incidence of major sequelae. 6. 6. If more than simple closure is to be considered gastric resection is the only procedure fundamentally sound. 7. 7. Gastric resection should be considered early if the patient remains symptomatic under treatment.