The basal application of hydrostatic pressure markedly affected differentiated and undifferentiated mammary epithelial cell monolayers. The reduction of transepithelial resistance may be interpreted as a protectivereaction. Differences in the increase of short circuit current may indicate time-dependent adaptive processes in epithelial cells exposed to hydrostatic pressure, in dependence of the differentiation status of the monolayers. We hereby provide a new approach for analysis of pressure-induced effects in mammary epithelial cell monolayers in varying differentiation states, in vitro.