We prepared a collagen sponge made of type I and III bovine collagen, glycosaminoglycans (GAG) and chitosan. Fibroblasts grown within the collagen sponge express a sixfold increase of their collagen synthesis, compared with fibroblasts embedded in a collagen gel. Moreover, collagen synthesis is twice as high in the collagen sponge than in a monolayer culture. The collagen sponge culture system promotes a dynamic model for us to perform studies on the regulations of collagen synthesis. Increased collagen production within the collagen sponge leads fibroblasts to reconstitute their own extracellular matrix, which should be more physiological than a bovine collagen gel.