The risk of stomach cancer was analysed in a cohort of 3470 patients who had had gastric surgery for benign disease between 1900 and 1969. In 87 patients (2.2%) stomach-stump cancer was diagnosed in the follow-up period 1970-84. By comparison with the total incidence of stomach cancer in the same region during the same time period, the observed versus expected ratio in the post-surgery group was 2.1 (p less than 0.001) and did not differ between men and women. At 5-10 years postoperative the risk of cancer was no different from that in the total population, whereas after 40-45 years it was 7.3-fold higher. The risk was unrelated to primary diagnosis or type of operation.