Development of the kidney is initiated when the caudal region of the Wolffian duct (WD) swells and then buds out into the adjacent metanephric mesenchyme (MM) induced by GDNF. Then FGF, HGF, BMP, MMP, integrin and adhesion molecules are expressed in the UB and MM result in branching morphogenesis, including the ureteric bud (UB) invation into the MM, the elongation of the UB and mesenchymal-epithelial transition (MET). Those molecules function in maintaining a balance of cell proliferation and differentiation to ensure normal formation of the branches. Also, there are parts of overlap and antagonist between those growth factors. This review focuses on the regulation of branching morphogenesis.