A multi-scale analysis method, called Empirical Mode Decomposition (EMD), has been proposed for analysis of nonlinear and non stationary data. The empirical mode decomposition is a method initiated by Huang et al. as an alternative technique to the traditional Fourier and wavelet techniques for examining signals. It decomposes a signal into several components called intrinsic mode functions. This paper deals with this new tool to detect usable speech in co-channel speech. We applied empirical mode decomposition to decompose the co-channel speech signal into intrinsic oscillatory modes. Detected usable speech segments are organized into speaker streams, which are applied to speaker identification system. The system is evaluated on co-channel speech across various Targets to Interferer Ratios (TIR). Performance evaluation has shown that empirical mode decomposition performs better than linear multi-scale decomposition by discrete wavelet for usable speech detection.