Abstract: The process of human embryo implantation is mediated not only by evolutionarily conserved mechanisms,but also by a mechanism unique to humans.Evidence suggests that the cell adhesion molecules,L-selectin and trophinin,play a unique role in human embryo implantation.Here,we describe the dual roles of mucin carbohydrate ligand for L-selectin and trophinin protein and ofthe trophinin-associated proteins bystin and tastin.We then describe trophinin-mediated signal transduction in trophectoderm cells and endometrial epithelial cells.This review also covers cadherin and integrin in human embryo implantation.