Research has been done into (1) the results of the surgical treatment of the perforated duodenal ulcer in 1983 in 122 patients in 8 university and 12 main training hospitals, and (2) into the possible changes of the surgical policy and the incidence before and after the introduction of cimetidine in the period 1970–1982. Most important changes in policy were the introduction of suture + HSV and a decrease of simple suture and partial gastrectomy. An average of 6 perforated duodenal ulcers per year per clinic was maintained in the period before and after the introduction of cimetidine. Under 40 years of age, male patients suffered far more perforations than female patients; over 70 years, female patients suffered twice as many perforations as male patients. Of the medicines used by patients before perforation (especially older patients), 45% had potentially mucosa-damaging characteristics. Of the patients younger than 60 years, 75% was hospitalized within 12 h; of the patients older than 60 years it was only less than 50%. There was no consensus on the use of antibiotics. Mortality rate was 19% (23 patients, all in the age group 60 years and older). The main cause of death was sepsis. Up until 1983, simple closure and truncal vagotomy + pyloroplasty seemed to be the most frequent surgical treatments.