Collagen, which is newly synthesized by the cellular component, is the major component of extracellular matrix in PVR membranes. The effects of transforming growth factor(TGF)-β in the synthesis of collagen were evaluated. Tissue culture of PVR membrane was incubated for 19 hours with or without TGF-β in the absence of serum. Newly synthesized collagen in the membrane were measured by a collagenase-digestion assay. The biosynthetically labeled collagens were analyzed on SDS-polyacrylamide gel electro-phoresis. Collagen synthesis was dose-dependently stimulated by TGFβ. At a concentration of 1ng/㎖ of TGFβ1or TGFβ2,at a concentration of 10ng/㎖, induced a 90-125% increase in collagen synthesis over that of controls. PVR membranes in culture synthesized predominantly type I, III and V collagen. In conclusion TGFβ are potent stimulants of collagen.