This paper presents an efficient and reliable method to extract parameters of a photovoltaic module (two-diode model) from datasheet at different environmental conditions, using a simple MATLAB-based algorithm. In this method, the number of parameters to be determined is six; it consists of a current source in parallel with two diodes. The first diode simulates the diffusion process of the minority carriers into the depletion layer, whereas the second diode corresponds to the recombination in the space charge region of the junction. This model requires only the coordinates of three key points of the I-V curve, i.e., the open-circuit voltage, the short circuit current and the maximum power point. This method is applied to a set of real PV module. This method is applied to a set of real PV modules of different technology.