Since protons play a key role in enzymatic reactions, the pH sensors have been widely used in various kinds of biosensing devices such as DNA sequencers, and enzyme sensors [1]. Comparing with conventional detection techniques, the potentiometric measurement has some advantages due to its simplicity of fabrication. Furthermore, it is obvious that the pH sensor combined with the wireless communication module becomes more useful for practical applications. In this study, we performed the pH monitoring of enzymatic reaction using the wireless module and Ir/IrOx pH sensor.