Fibroblasts are mesenchymal cells which came from the embryonic mesoderm. They are useful for a wide range of cellular and molecular studies as they are one of the easiest types of cells to grow in culture. Their durability also makes them amenable to a wide variety of manipulations ranging from studies employing gene transfection to microinjection. There is evidence that fibroblasts in various parts of the body are intrinsically different. Fibroblasts secrete a non-rigid extracellular matrix that is rich in type I and/or type III collagen. Human bladder stromal fibroblasts (HBdSF) also secrete FGF-7, which interact primarily with bladder epithelial cells. FGF-7 secreted by HBdSF is essential for stimulating the formation of a multilayered stratified bladder epithelium. Human Bladder Stromal Fibroblasts are also useful tools to stablish disease models for High Throughput and High Content Screening.