The Authors considers 49 cases of perforated duodenal ulcers in free peritoneum, observed in 6 years from 1972 to 1977. They are quite exclusively males (9 : 1), aged from 22 to 80 years, observed from over 4 to 72 hours from effective perforation. After the bare necessities of their hydroelectrolitics balancing, 20 cases came to a simple suture, 29 to an ulcer excision, vagotomy and pyloric plastics. No post operative complications were noted in the two groups: mortality has been of 2 patients in the first group and of no one in the second; pathological ulcerous relaps have been of 47% in the first group and 0 in the second one, with from over 15 months to 6 years controls. By clinical, radiological and andoscopical examinations the AA, concludes that the best therapy treatment in perforated duodenal ulcers--except very particular cases--consists at the same time in the treatment of ulcerous pathology and its complications, with vagotomy completed by piloric plastics sec. Judd, and ulcer's excision.