Ulcerative colitis is a diffuse inflammatory disease of the mucosal lining of the colon and the rectum without an apparent cause. It is common in European and North American countries, but rare in Korea. We reviewed 59 cases, who were diagnosed by clinical findings, barium enema, and colonoscopic biopsy from March 1988 to Febrary 1996 at the EWHA University hospital. The most prevalent age group was the third decade(32.20%) and a male to female sex ratio was 1 : 1.68 with 22 males and 37 females. The most prominent clinical symptoms were bloody stool(84.7%), diarrhea(61.0%), and abdominal pain(53.2%). The duration of the symptoms was less than 1 month in 38.98%, between 1 and 5 month in 16.9%, more than 6 months in 43.95%. For the anatomical site of the lesion, 28.8% of the cases were in the rectum alone, and 23.7% of the cases were in the entire colon. The laboratory fading showed Hemoglobin level below 10 g/dL in 13 of the 57 cases studied, and an albumin level below 3.0 g/dL in 10 of the 54 cases, ESR below 20 mm/hr in 2 of the 17 cases studied. The endoscopic examination showed positive findings in all of the 58 cases among the 58 cases studied. The barium enema examination showed positive findings in 26 cases among 31 cases. Of 59 cases that were studied, 58 cases were treated by medical therapy, and showed relative improvement but 1 of 59 cases had no improvement. Among the cases that showed a significant improvement, 31 cases had relapsed. Of the 59 cases, 7 cases were operated and completely cured.