Skin fibroblasts from chick embryos of 7 and 14 days incubation have been tested for their ability to bind, internalize and degrade [3H]-hyaluronan. Seven-day fibroblasts internalize and degrade a greater amount of labelled hyaluronan than 14-day cells. The implications of these findings in the regulation by the fibroblasts of extracellular matrix composition in glycosaminoglycans are discussed.