It is well known that patients with long-standing inflammatory bowel disease (IBD), ulcerative colitis (UC) or Crohn's disease(CD) are at increased risk for developing colorectal cancer (CC). Before adenocarcinoma develops, the intestinal epithelium progress through a premalignant phase of dysplasia, which can be identified via mucosal biopsy and routine tissue histology. Surveillance colonoscopy and prophylactic colectomy for dysplasia or asymptomatic cancer is advised as a method of reducing cancer-related mortality. Many physicians suggests that surveillance for extensive colitis should begin after 8 to 10 years of disease, and surveillance for left-sided colitis should begin after 15-20 years. Colonoscopy is recommended with frequent biopsies, at least every 10 cm in all four quadrants, and with biopsy of any suspicious lesion. The emerging field of colon cancer genetics has identified several important tumor markers that have potential to improve sensitivity for detection of early neoplasia.