The frequency of inflammatory bowel disease in the Faroe Islands was estimated retrospectively for the years 1964 to 1983. A pronounced increase in the incidence of ulcerative colitis from 2.1 to 12.8 per 100,000 was found. The mean incidence in the period was 7.5/100,000; the prevalence was 157.3/100,000 on 31 December 1983. The change in frequency of Crohn's disease was insignificant, and the incidence of the disease was low compared with in other countries (1.75/100,000); the prevalence was 31.8/100,000 on 31 December 1983. The increase in incidence rate of ulcerative colitis was distributed equally between the two sexes, and a pronounced increment was found among young women.