In this paper, a robust switching signal estimation approach is presented for a class of uncertain nonlinear switched systems using a sliding mode robust observer on the continuous state vector of system. In this approach, the estimation of switching signal is achieved at a bounded and arbitrary small time in spite of un-modelled uncertainties. The developed estimation technique can also be employed on mode-dependent control methods to reach a practical controller for nonlinear switched systems with the inaccessible switching signal. The simulation results illustrate the capability of proposed method.