Colorectal cancer is one of the most common cancers in Western countries. The long natural history of colorectal cancer provides opportunities for detection of early stage cancer and for prevention of cancer by removal of adenomas. An effective screening technique should significantly reduce morbidity and mortality in the population. Several tests are available to screen healthy subjects at average risk for colorectal cancer: total colonoscopy, combined sigmoidoscopy and faecal occult blood test (FOBT), FOBT alone. At the present time clear evidence for the most effective screening strategy is not available. Colonoscopy screening in Germany needs an adequate tool to evaluate the programme. Follow up is essential and cancer registries would be an important partner.