Classical cadherins are single-pass transmembrane proteins mediating adhesive interactions between animal cells. As such, they play key roles during morphogenetic movements, in cell sorting and in tissue integrity. Being positioned at the cell-cell interface, cadherins are most likely important players in mechanotransduction pathways. This review briefly outlines our current understanding of the biochemical and biophysical basis for various adhesive properties of cadherins and the ensuing intercellular adhesive strength and specificity. We summarize the attempts to explain cadherin specificity from their ultrastructural features and their adhesive behavior at the single molecule level. The role of cadherin clusters and cooperative binding is then reviewed. Lastly, we consider the attempts to understand the link between local stress and the adhesive properties of cadherin-mediated junctions.