A geographically based cohort of 37 children with ulcerative colitis has been derived by sampling from Scottish Hospital In-patient Statistics. Surgical histories were examined and analysed by actuarial methods, and the major operations performed were compared with operations for ulcerative colitis in the Lothians' Surgical Audit. Fourteen of the 37 patients had a total of 26 operations (15 major, 11 minor). Sixteen per cent had major surgery within 5 years of onset of symptoms, and the types of operation were similar to those recorded in Lothians' Surgical Audit. Operation rate was significantly lower than that for a parallel cohort of patients with Crohn's disease. With a mean follow-up of 7.4 years, seven (19 per cent) patients have a permanent stoma and there has been one death.