A histological and molecular dichotomy has been recognised whereby conventional adenomatous polyps precede the development of colorectal cancers harbouring APC mutations and aneuploid chromosomes, in contrast to serrated polyps that develop into cancers showing BRAF mutation and widespread DNA methylation (CpG Island Methylator Phenotype, CIMP). This presentation will focus on recent molecular and histological developments in our understanding of serrated neoplasia.