We evaluated trends in peptic ulcer surgery among residents of Rochester, Minnesota, where medical care delivered to the population by all providers is well documented. The incidence of elective operations on previously unoperated patients declined dramatically during the 30-yr study period, from 49/100,000 population per year in 1956-1960 to 6/100,000 per year in 1981-1985. The decline was greatest for men with duodenal ulcer, less for men and women with gastric ulcer, and least for women with duodenal ulcer. These trends were established long before the introduction of H2-receptor drug therapy in 1977. In contrast to elective operations, the incidence of emergent operations remained at about 10/100,000 population per year. Perhaps because of an increasing proportion of emergency operations, overall survival appeared to worsen from the first decade of study to the last; but, after adjustment for age at operation and sex, no difference in survival over time was detected.