E-cadherin and beta-catenin are cell-cell adhesion molecules, which are thought to play an important role in trophoblastic differentiation and remodelling during gestation. Their expression may be altered in pathological conditions with trophoblastic invasion. In this study, we used immunohistochemical methods to study the pattern of expression of E-cadherin and beta-catenin in villous trophoblastic tissue in normal and pathological pregnancies. In villous trophoblastic tissue, E-cadherin had a membranous distribution, whereas beta-catenin had a mixed-membranous and granular cytoplasmic distribution. The levels of expression of E-cadherin and beta-catenin correlated with each other. From first to third trimesters, the expression of both E-cadherin and beta-catenin showed a decreasing trend. In preeclampsia, there was an up-regulation of E-cadherin and beta-catenin expression. In placenta accreta, the level of expression of both did not differ from that in normal third-trimester placenta. In gestational trophoblastic diseases, there was a general trend of down-regulation of both E-cadherin and beta-catenin. Altered expression of E-cadherin and beta-catenin may play a role in the development of normal and pathological placentas.