Explants of neonatal murine stria vascularis were maintained in vitro to evaluate the process of morphogenesis in cochlear tissue. Immunohistochemical and electron microscopic studies showed that the relatively undifferentiated cells in culture attained morphological features characteristic of the stria vascularis cell types in vivo (marginal, intermediate and basal cells). The three kinds of cells formed a trilaminated tissue, with the epithelial cells bordering the culture medium, basal-like cells resting on the culture substrate, and the melanocytes layered between. Furthermore, approximately 20% of these cultures displayed a unique alignment of melanocytes which formed elongated bands along the contour of the tissue edge. However, only limited cell extensions were formed between different cell types and interdigitation amongst these processes was abbreviated. Thus, cells from different embryological origins divided, migrated and reestablished appropriate cell-to-cell associations to form a layered tissue similar to the stria vascularis in vivo.