In this chapter we describe a reliable and reproducible method for the selective propagation and culture of renal fibroblasts derived from explantation of renal cortical tissue in vitro. The chapter outlines how primary renal interstitial fibroblasts are derived from explants grown in medium supplemented with foetal calf serum. The subculture of confluent cells and their ultimate characterisation as fibroblasts through immunohistochemical and immunocytochemical techniques are described in detail.