the authors describe the plating of polypyrrole utilizing stm tips as the plating probe. pyrrole is oxidized in electrolyte solution to form a polymer that can switch between conducting and insulating states. the combination of small effective tip surface area, small tunneling gap and a short applied-pulse duration results in nanoscale size features of polypyrrole plated on highly oriented pyrolytic graphite. it is shown that tip-induced deposition can proceed only above a certain threshold pulse potential value polypyrrole was deposited from two types of electrolyte solution' one containing supporting electrolyte and the monomer and the other containing, in addition, 1000 units ml/sup -1/ of the enzyme glucose oxidase. the reason for studying the deposition in the solution containing the enzyme is to simulate the conditions of fabricating an enzyme-immobilized biosensor. the results presented for pyrrole/glucose oxidase deposit agree with earlier macroscale data for this biosensor