Steady state amperometric measurements of hydrogen peroxide in aqueous medium was performed by an enzyme electrode which was developed by electrostatic immobilization of the horseradish peroxidase, HRP, in Poly(vinyl ferrocenium perchlorate), PVF+ClO4, film, Amperometric measurements were performed at an applied potential of + 0.7 V (vs. SCE). The effects of working temperature, enzyme concentration, film thickness and dissolved oxygen on the response of the electrode were elucidated. The responses of the PVF+E- electrode, PVF+ ClO4- coated electrode and uncoated Pt electrode were compared. The activation energy and the apparent Michaelis-Menten constant were calculated for enzyme electrode system. The linear working range, the sensitivity and the stability of the biosensor were also determined. Mechanisms for the operation of the electrode with and without immobilizied enzyme in the polymer matrix are proposed.