The feasibility of functionalizing the surfaces of the electrically conducting polypyrrole (PPY) film with biomolecules was demonstrated with an enzyme, glucose oxidase, and an anticoagulant, heparin. The biomolecules remained active after immobilization and the choice of the "linkage groups" attaching the biomolecules to the PPY surface can play an important role in the activity of the biomolecules. The use of a viologen to link the glucose oxidase to the PPY surface enables the PPY film to act as a biosensor with a wide linear range and high electrochemical response. Similarly, poly(ethylene glycol) methacrylate (PEGMA) graft copolymerized PPY films immobilized with heparin are more efficient in minimizing platelet adhesion than that without the PEGMA. An advantage of using electrically conductive PPY films as a substrate is that electrical stimulation can be carried out to further enhance the effect of the heparin.