This article, which grew out of the Roger C. Haggitt Gastrointestinal Pathology Society Forum presented in Vancouver, Canada, March 6, 2004 as part of the annual meeting of the United States-Canadian Academy of Pathology, reviews the morphologic and molecular evidence for the concept of various polyps in the general category of serrated polyps of the large intestine, in particular the lesion known as the sessile serrated adenoma, and provides a conceptual framework for diagnosis of these lesions.