Although it is generally accepted that the risk of colorectal cancer in patients with ulcerative colitis is increased compared with the general population, the management of this increased risk remains controversial. Patients with pancolitis of > 8 years duration should consider periodic colonoscopic surveillance or prophylactic colectomy. For patients unwilling to undergo prophylactic colectomy, colonoscopic surveillance annually or biennially is recommended. High-grade dysplasia or low-grade dysplasia in association with a lesion or mass is an indication for colectomy when confirmed by 2 pathologists. Repeat colonoscopic surveillance (in 3-6 months) or colectomy is recommended for confirmed low-grade dysplasia.