Ulcerative colitis is an idiopathic chronic inflammatory bowel disease and its incidence in Korea has rapidly increased over the past two decades. Since ulcerative colitis is associated with increased risk for colorectal cancer, annual or biannual colonoscopy with four quadrant random biopsies at every 10 cm segments has been recommended for surveillance of colitic cancer in patients with long standing left-sided or extensive colitis. Recent epidemiologic data and meta-analysis suggest that the increment of colorectal cancer risk in ulcerative colitis was not larger than that of previous studies. Moreover, in addition to the extent and duration of colitis, other risk factors such as family history of colorectal cancer, primary sclerosing cholangitis, stricture, pseudopolyps, and histologic severity of inflammation have been recognized. As a result, updated guidelines provide surveillance strategies adjusted to the individual patient's risk for colitic cancer. Regarding surveillance method, target biopsy under panchromoendoscopy is preferentially recommended rather than random biopsy.