Colorectal cancer is the most common cancer of the digestive tract in western countries. In Korea, its mortality rate has markedly increased in recent 15 years. The mortality of colon cancer can be decreased by proper screening and subsequent polypectomy. Early colon cancer is defined as colon cancer that infiltrates within mucosa and submucosa regardless of lymph nodes invasion and has favorable outcomes. It can be easily removed by endoscopic procedures. The depth of submucosal invasion should be determined before endoscopic removal by various parameters, such as shape, pit patterns by magnifying endoscopy, and endoscopic ultrasonography. After endoscopic removal, the tissue specimen should be carefully examined for the completeness of the removal.