The hamartomatous polyposis syndromes constitute a group of at least six different rare diseases that may require endoscopic management. There are no prospective studies to prove the validity of any management approaches, but knowledge of the genetic basis and pathological manifestations of these diseases can be used to tailor approaches to intervention and surveillance in affected patients. Certain of these diseases have very high predispositions to cancer, which requires particular attention. The development of techniques to evaluate the small intestine and remove polyps nonsurgically has been of particular benefit for these patients.