Endothelial cells culture can be considered a reliable method for investigating about granulation tissue production in wound healing and for evaluating the pharmacological action of some chemicals on granulation tissue development. Endothelial cells have been obtained from human umbilical cords after trypsin treatment and their endothelial origin has been demonstrated by light microscopy, by immunofluorescence against factor VIII associated protein and by the platelet adhesion assay. The influence of fibronectin as substratum and of hyaluronic acid as soluble factor on adhesion and growth of endothelial cells has been investigated. Both these substances, but especially hyaluronate, determine a better attachment and an increase in the growth rate when compared with control cultures plated on plastic substratum and without hyaluronic acid in the culture medium.