Cadherins are Ca(2+)-dependent cell adhesion molecules that play fundamental roles in animal development and homeostasis. A number of cadherins contain conserved binding sites for catenins in their cytoplasmic region that are important for the adhesive function of these cadherins by mediating their interaction to the cytoskeleton. However, most cadherins lack apparent binding sites for catenins and their cytoplasmic interacting partners are mostly unknown. In this paper, we show, using bioinformatics, that a number of insect and vertebrate cadherins lacking catenin-binding sites contain conserved consensus sequences for C-terminal PSD-95/Discs-large/ZO-1 (PDZ)-domain-binding sites. This suggests that PDZ-domain-containing proteins are common cytoplasmic interacting partners for cadherins lacking catenin-binding sites.