BACKGROUND/AIMS: In Korea, Crohn's disease is rare and only few studies about clinical features have been reported. To evaluate the clinical features of Crohn's disease in Korea, we performed this clinical study. METHODS: We retrospectively reviewed the medical records of 213 patients with Crohn's disease registered in Seoul National University Hospital between 1975 and 2000. RESULTS: The ratio of annually diagnosed Crohn's disease to ulcerative colitis has increased from 0.2% before 1990 to more than 0.5% in 1995. The male/female ratio was 1.8:1, and the age of onset peaked in the teens. Forty-three percentages of the cases had a history of taking anti-tuberculous medications. The disease locations were the small bowel in 19% of the cases, colon in 23%, and both of the small bowel and colon in 58%. Major symptoms were abdominal pain (93%), weight loss (86%), and diarrhea (73%). Serum antibody to Saccharomyces cerevisiae were positive in 50%. Regarding the outcomes of medical treatment, 86% of the treated group showed improvement, but the remaining 14% showed poor response. Among the 24 cases of non-responding group, 13 cases received operation and 10 cases maintained the treatment. Short-term outcome was poor in cases with internal fistula. Cumulative symptomatic relapse rates were 62% in 5 years, and 88% in 10 years. Long-term clinical courses were remission in 24% of the cases, mildly symptomatic in 21%, and in a state of repetitive relapse and remission in 55%. CONCLUSIONS: Crohn's disease in Korea seems to be apparently increasing. After a long-term course, patients are more likely to be mildly symptomatic or in a state of repetitive relapse-remission.