Cadherins, named for calcium-dependent adhesion, are a class of type-1 transmembrane proteins that are calcium dependent cell adhesion proteins. The Cadherin superfamily includes cadherins, protocadherins, desmogleins, and desmocollins, and more. In structure, Cadherins share cadherin repeats, which are the extracellular Ca2+-binding domains. Cadherin-9, so far only described in the neural system, was identified as a reliable surface marker for renal fibroblasts. Cadherin-9 represents a novel and reliable cell surface marker for fibroblasts in healthy and diseased kidneys. Together with the established marker molecules FSP1, CD45 and α smooth muscle actin, Cadherin-9 can now be used to differentiate the heterogenic pool of renal fibroblasts into resident and activated fibroblasts, immigrated bone marrow derived fibroblast precursors and cells in different stages of epithelial mesenchymal transition.