In this paper, large signal model for power MOSFET devices is presented. The proposed model includes quasi-saturation effect and describes accurately the electrical behavior of the power MOSFET devices. The large signal model elements will be provided based on the device structure. Furthermore, the model parameters are extracted from measurements considering the voltages depending effect of the nonlinear gate-source, gate-drain and drain-source interelectrode capacitances. Excellent agreements will be shown between the simulated and the datasheet data. Finally, a description of the model will be provided along with the parameter extraction procedure.