Fibroblasts are mesenchymal cells derived from the embryonic mesoderm. They have been extensively used for a wide range of cellular and molecular studies. This is mainly because they are one of the easiest types of cells to grow in culture, and their durability makes them amenable to a wide variety of manipulations ranging from studies employing gene transfection to microinjection. There is good evidence that fibroblasts in different parts of the body are intrinsically different. Fibroblasts within tissues are exposed to a dynamic mechanical environment, which influences the structure integrity of both healthy and healing soft tissue. Fibroblasts secrete a nonrigid extracellular matrix that is rich in type I and/or type III collagen. As cells of mesenchymal origin, 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. HBdSF from AcceGen Biotech Research Laboratories are isolated from human bladder tissue. HBdSF are cryopreserved at secondary culture (passage one) and are delivered frozen. Each vial contains >5 x 10^5 cells in 1 ml volume. HBdSF are characterized by immunofluorescent method with antibody to fibronectin. HBdSF are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HBdSF are guaranteed to further expand for 15 population doublings at the condition provided by AcceGen Biotech Research Laboratories.