The course and prognosis of 308 patients with ulcerative colitis who visited Tohoku University Hospital during the period from 1954 to 1987 were investigated. Based these investigations, the following results were obtained. 1) In 27.6% of patients with proctitis, extension to the proximal colon developed during the observation period. 2) Surgical intervention was necessary in 33.9% of patients with total colitis and in 9.7% of those with left-sided colitis. 3) Of 1,566 patient-years in which the course was observed, 988 (63.1%) were active-years. When the course of ulcerative colitis was analyzed according to the duration and extent of involvement, the frequency of the attack-years in patients with proctitis or left-sided colitis steadily decreased with time. However, that of total colitis was constant, 65-85%, regardless of the follow-up period. Patients younger than age 20 at onset were prone to relapse during their course, compared with patients older than 20. 4) Ten patients died from causes related to ulcerative colitis in our hospital: 5 of them due to postoperative complications. Two patients developed colorectal cancer accompanying ulcerative colitis. 5) With respect to the cumulative survival rate, the 95% confidence limits of the observed curve was lower than the expected curve during the first 2 years and 12-16 years after the onset. The main causes of death were postoperative complications in the former and unrelated deaths of older patients in the latter.