From a prospective epidemiological and radiological study of peptic ulcer disease in the northern part of Norway, relations between occupation and the occurrence of new peptic ulcers are presented. Over a 3-year period 1861 patients with dyspeptic complaints, 557 women and 1304 men belonging to 12 different occupational groups, were studied. Special attention was paid to the fishing population, constituting 2488 men and only 55 women. In the period studied 87 gastric ulcers and 118 duodenal ulcers were found. A statistically significantly higher incidence of both gastric and duodenal ulcers was found in fishermen than in the other groups. Furthermore, significantly higher incidences of duodenal ulcers were found in men occupied in 'land or water transport'. Compared with the total male population at risk in the area studied, significantly higher incidences were found for duodenal ulcer in fishermen. The present study confirms prior reports both from Scotland and from North Norway, showing an increased incidence of peptic ulcers in the fishing population.