In order to synthesize biocompatible materials that are used for artificial organs, hybridization of materials with biologically active substances seems to be most effective. To prevent coagulation upon blood/materials contact, hybridization with the materials of the repressor of coagulation factors or platelet and the activator of fibrinolysis has been done. Simultaneous hybridization of two kinds of biologically active substances has also been found effective. Recently, cell/materials hybridization is particularly popular. For this type of hybridization composite materials have been developed that are convenient for cell lining or in vivo compatible with living cells. This method will lead to the control of cell functions with suitable materials and a future development is expected.