Familial adenomatous polyposis is an autosomal dominant disease that includes early development of up to thousands of colorectal adenomas and several extracolonic manifestations. All untreated patients will develop colorectal adenocarcinoma. The treatment of choice is colectomy and ileorectal anastomosis, but restorative proctocolectomy may be considered in selected cases. Polyposis patients treated with ileorectal anastomosis should be followed for life, with regular proctosigmoidoscopy and destruction of new adenomas. Furthermore, regular gastroduodenoscopy should be carried out because of frequent occurrence of premalignant duodenal adenomas. The prognosis is good after prophylactic colectomy in patients without carcinoma. All first degree relatives of affected family members should be examined regularly with proctosigmoidoscopy from the age of ten, and prophylaxis should be organised using a national or regional polyposis register. The recent detection of a specific gene for familial adenomatous polyposis is a long step forward, and several problems may be solved by increasing international cooperation.