Crohn's disease used to be recognized as a rare inflammatory bowel disease in Korea, but current accumula- tion of sporadic case reports suggests a gradual increase of its inridence. Systemic studies, however, with clinical follow-up after treatment have not been fully assessed in the era of advanced colonoscopic approach. This article describes the clinical and pathologic findings of 15 cases of Cron's disease together with their clinical follow-ups with medical therapy, experienced during a period from October, 1978 to July, 1990. The results are summarized as follows: 1) The male-to-female ratio was 3,1, and the mean age was 25.5 years. The duration of symptoms was 2 months to 4 years, and the mean duration was 26 months. Common symptoms and signs included diarrhea, abdominal pain, weight loss, fever, etc., and the extraintestinal manfestations were rather scarce in these study cases. Anemia, increased ESR, throm-bocytosis, and hypoalbuminemia were frequent findings. 2) Colonoscopic and/or radiologic studies showed skipped lesion (80%), cobblestone appearance (67%), and longitudinal ulcer (47%) in order of frequency. The most common involved sites were the small bowel alone (27%), ileocolitis (60%), and the colon alone (13%). 3) Most of the patients (67%) responded well to medical therapy for a short-term period, and there was a good correlation between the subjective symptoms, colonscopic or radiologic findings, and Crohn's disease activity index. 4) Compared with cases from Western countries, the sex ratio in this study showed a male predominance, extraintestinal manifestation was rare, many patients (53%) had a past medical history of failure with anti-tuberculosis medication, and a good correlation existed between the subjective symptoms an6 objective examination. With the above findings, we assume that Crohn's disease is still a rare inflammatory bowel disease in Korea which requires a differential diagnosis with intestinal tuberculosis. It also seems more likely that in patients with clinical features of intestinal tuberculosis but who did not show any evidence of clinical improvement, including objective findings of intestinal ulcer, in spite of prolonged anti-tuberculosis medication lasting for several months, a possibility of Crohn's disease should be considered.