The progression of chronic renal failure results from the process of fibrosis, which involves the proliferation of renal fibroblasts and the secretion of extracellular matrix proteins (ecm) by these cells. Collagen is the main component of ecm. Renal collagen types in normal kidney and in renal diseases were described. Mediators that stimulate fibroblast proliferation, collagen turnover and factors its regulating were discussed.