AIM: To determine the clinicopathologic characteristics of surgically treated ulcerative colitis (UC) patients, and to compare the characteristics of UC patients with colitis-associated cancer (CAC) to those without CAC. METHODS: Clinical data on UC patients who underwent abdominal surgery from 1980 to 2013 were collected from 11 medical institutions. Data were analyzed to compare the clinical features of patients with CAC and those of patients without CAC. RESULTS: Among 415 UC patients, 383 (92.2%) underwent total proctocolectomy, and of these, 342 (89%) were subjected to ileal pouch-anal anastomosis. CAC was found in 47 patients (11.3%). Adenocarcinoma was found in 45 patients, and the others had either neuroendocrine carcinoma or lymphoma. Comparing the UC patients with and without CAC, the UC patients with CAC were characteristically older at the time of diagnosis, had longer disease duration, underwent frequent laparoscopic surgery, and were infrequently given preoperative steroid therapy (P < 0.001-0.035). During the 37 mo mean follow-up period, the 3-year overall survival rate was 82.2%. CONCLUSION: Most Korean UC patients experience early disease exacerbation or complications. Approximately 10% of UC patients had CAC, and UC patients with CAC had a later diagnosis, a longer disease duration, and less steroid treatment than UC patients without CAC.