An analysis was made of survival times and causes of death of patients given local irradiation in small dosage during 1948--1960. The study involved 61 patients with peptic ulcers in whom hyperacidity was treated by partial gastrectomy and gastric irradiation, and their mortality was compared with that of 61 age- and sex-matched gastrectomized but nonirradiated control patients. For both groups the survival rates were related to "normal population" survival rates calculated from age-, sex- and year-specific mortality rates for the population of Victoria. Ten years after irradiation the relative survival rates of the irradiated and control groups began to diverge, due to more deaths than expected in the irradiated group. The irradiated group had a significantly increased number of deaths due to cancer, particularly carcinoma of the stomach, as well as an increase in deaths not caused by cancer. The mortality of the nonirradiated control patients was not significantly greater than that of the normal population.