In this paper, a two step approach for backlash identification is proposed. In the first step, using a physical relation between backlash amplitude, the vibration produced by backlash and the backlash input, a pre-estimation is established. In the second step, a least square criterion is minimized around the pre-estimation. The method is tested in simulation on a system consisting of a driving motor and a load coupled to it through a gear and a shaft. The method is simple and can be easily generalized to systems containing many shafts. The simulation results confirm the good performance of the method.