Specific adhesion among like cells is a key determinant of the architecture of tissues. Homophilic (like binds like) adhesive interactions between cells are mediated by cadherins. These integral membrane glycoproteins have a crucial role in tissue morphogenesis during development and the maintenance of tissue integrity in adults. There is also an increasing recognition of a regulatory role for cadherins in a variety of cell functions, including cell migration. The recent identification of cadherin-11 expression in fibroblast-like synoviocytes (FLSs) has shed light on the mechanisms of synovial tissue organization and differentiation. Moreover, cadherin-11 expression in FLSs might also provide insight into pathways that determine the mesenchymal tissue response of the synovium to inflammation.