Colorectal cancer is the second leading cause of death in Northern countries and need a national screening program to reduce mortality and improve quality of life. Screening has to be cost-effective and acceptable for patients. Many screening tools, invasive or not, are existing and often debated: FOBT, sigmoidoscopy and complete colonoscopy. New tools are in development and have to be evaluated in current practice: virtual colonoscopy, new endoscopic technologies, DNA on faeces or proteomics with markers in serum.