In recent years, due to the problems of the energy crisis, harnessing of the photovoltaic energy found its high importance and usefulness in many industrial applications. However, several methods has been developed such as P & O (perturb and observe) to operate the photovoltaic generator at the maximum point of power and thus to permanently provide to the load a maximum power. Due to that the reliability of the power DC-DC converters in solar PV systems is important in many safety industrial applications, the development of fault detection and identification methods has profit a lot of interest. Accordingly, this paper presents an open-circuit and short-circuit MOSFET fault for a boost converter in solar PV systems. The proposed fault detection method requires only the current and voltage sensors to detect the MOSFET fault. Furthermore, the simulation results prove the effectiveness and the performance of the proposed fault detection method.