New technologies in molecular biology will allow the improvement of screening, diagnosis and prognosis of colorectal cancer patients. For example the determination of germline mutation in APC or in mismatch repair genes in patient with familial adenomatous polyposis or with HNPCC is now possible. The clinical surveillance can be restricted to the patients with these germline defects. More over the knowledge of somatic genetic alterations in colorectal cancer cells seems to be useful in the determination of prognosis of these patients or in order to predict the chemotherapy response.