The complexity and heterogeneity of the human nephron with regard to cell types make well-defined in vitro systems of renal cells valuable for studies of the pathogenetic mechanisms involved in nephrotoxicity. In our laboratory renal proximal tubule cells (PTC) and collecting duct cells (CDC) have been isolated, cultured and characterized from cadaver kidneys (postmortem time <24 h) for use in studies of renal cytotoxicity induced by therapeutics and bacteria. PTC seeded at 10<sup>6</sup> cells/ml formed confluent monolayers within 7 days. Histochemical markers were used to determine the origin of the cell cultures. Cells were negative for factor VIII, positive for cytokeratin and γ-glutamyltransferase (GGT), and bound winged pea lectin. CDC, isolated from the renal papillae, formed monolayers within 14 days of seeding. CDC were negative for factor VIII and GGT, positive for cytokeratin and bound peanut lectin. PTC and CDC isolates and cultures exhibited typical epithelial cell ultrastructure: cell junctions, intermediate filaments, microvilli, and numerous mitochondria. The morphological and histochemical evidence confirms that PTC and CDC can be isolated and cultured for use in in vitro studies.