We have studied transcription, expression, and membrane localization of components of the E‐cadherin‐catenin complex stage by stage during mouse preimplantation development. Maternal E‐cadherin and α‐ and β‐catenin are stored as mRNA and/or protein in unfertilized eggs and are already assembled into a protein complex at this stage. After fertilization, it is likely that they mediate adhesion of early‐stage blastomeres. Biosynthesis of plakoglobin is delayed relative to the other components. The temporal mRNA and protein expression patterns of the components of the cadherin‐catenin complex correlate with the presence or absence of potential cytoplasmic polyadenylation elements (CPEs) in the 3′‐UTRs of the respective cDNAs. Our results suggest that the components of the E‐cadherin‐catenin complex derived from both maternal and zygotic gene activity are increasingly accumulated and stored in a nonfunctional form during early cleavage stages and are ready to be used for compaction and the formation of the trophectodermal cell layer. © 1996 Wiley‐Liss, Inc.