Crohn's disease is a rare disease in Korea, and only 45 cases have been reported during the period of 34 years from 1952 to 1985. The male to female ratio was about 1.3 to 1 with a slight preponderance of males. The age at diagnosis ranged from 8 to 72 (mean 35.5) years, and the peak incidence occurred in the 3rd, 4th and 5th decades and declined thereafter. More than two thirds of the cases had a grossly demonstrable lesion involving the small bowel, including the terminal ileum. The proportion of patients with macroscopic disease continued to the large bowel alone was only 15%. Abdominal pain was common, presenting in 89% of the patients, while such symptoms as fever, hematochezia and diarrhea were not common. Abdominal mass was palpable in more than half the cases, which made it difficult to differentiate Crohn's disease from cancer of the colon, especially in cases with a predominant infiltration of the bowel wall and a secondary ulcer formation. That is one of the reasons why most cases in Korea have been reported by surgeons. A wide variety of complications were present, of which small bowel obstruction was the most common. Other complications were free perforation, malnutrition, fistula formation, hemorrhage and abscess formation, in decreasing order. The incidence of symptomatic perianal disease was only 11%, and this might be due to the small proportion of the disease confined to large bowel. Extraintestinal manifestations were also rare, and only three patients presented symptoms of arthritis. Other systemic features such as liver disease, skin lesion, eye complications were absent.