Bone marrow stromal cells are a heterogeneous cell population containing adult stem and progenitor cells with a remarkable proliferative and differentiation capacity. In the present study, we established a co-culture of marrow stromal cells and bronchial epithelial cells of human origin to evaluate the differentiation potential of the mesenchymal stem cells and progenitors to differentiate across traditional lineage boundaries towards the epithelial phenotype. The formation of confluent and stable co-cultures is influenced by cultivation conditions for both pre-amplification, as well as in the co-culture. These factors include the medium composition, cell density of the inoculum and composition of the protein substratum in the co-culture. Through a trial-and-error approach, we selected the cultivation conditions that stimulate cell growth during amplification of bronchial epithelial cells and the formation of confluent and stable co-cultures. The latter was measured as the transepithelial electrical resistance. Epithelial differentiation of marrow stromal cells would expand their therapeutic application to a wider variety of tissues in regenerative medicine.