The detection of speech from silence (actually background noise) is essential in many speech-processing systems. In real-field applications, the correct determination of voice segments highly improves the overall system accuracy and minimises the total computation time. This paper1 presents a novel robust and reliable speech detection algorithm to be used in a speaker recognition system. The paper first introduces some basic concepts on speech activity detection and reviews the techniques currently used in speech detection tasks. Then, the proposed speech/non-speech detection algorithm is described and experimental results are discussed. Conclusions about the algorithm performances are finally presented.