Colorectal cancer (CRC) ranks first in incidence and third in cause of cancer death for both men and women in Taiwan. Early detection and removal of precancerous colon polyps and CRC may reduce both incidence and death rates related of CRC. It is recommended to begin screening at age 50 for asymptomatic persons who are at average risk. High-risk patients should have regular colorectal surveillance. Several screening methods are used to detect CRC lesions. Colonoscopy is the best method and final assessment step for detection of CRC.