While there are four times as many duodenal as gastric ulcers in Europe and the United States, previous studies have shown gastric ulcers to be more common in the Arctic regions of Norway. To investigate a possible change in the duodenal-to-gastric ulcer ratio, the incidence rate of first-time peptic ulcer in a well defined population in Northern Norway was studied by registration of all examinations of the upper digestive tract from 1983 to 1984. In this population, 5.3% were examined by endoscopy (52.5%) or a barium meal (47.5%). The incidence rates of duodenal and gastric ulcers were 1.4 and 0.8 per 1,000 per year, resulting in a duodenal-to-gastric ulcer ratio of 1.7:1. Although this ratio is higher than in a previous study (1.1:1), the pattern of peptic ulcer disease in northern Norway is still different from that in the rest of Europe.