Abstract-This paper describes the detection principle of a hydrogen peroxide sensor based on the electrolyte metal oxide semiconductor field effect transistor ( E MOSFET) and possibilities of using different types of redox materials as the gate material for the sensor with respect to the sensitivity and detection limit. After discussing the fundamentals of hydrogen peroxide detection and a short description of the E MOSFET characteristics in terms of its threshold voltage, the basic measuring principle of hydrogen peroxide using the E MOSFET is shown. The E MOSFET with electro-active gate materials such as iridium oxide, potassium ferric ferrocyanide, and Os polyvinylpyridine containing peroxidase, have been studied. These different materials are compared with each other with respect to their sensitivity, detection limit, and stability. The sensitivity of the sensors is improved by applying an external current between the gate and the solution.Index Terms-E MOSFET, hydrogen peroxide sensor, redox material.