An important problem in speech processing is to detect the presence of speech in a background of noise. This problem is often referred to as the endpoint location problem. By accurately detecting the beginning and end of an utterance, the amount of processing of the speech data can be kept to a minimum. The algorithm proposed for locating the endpoints of an utterance is based on two measures of the signal, namely, zero crossing rate and energy. The algorithm is inherently capable of performing correctly in any reasonable acoustic environment where the signal-to-noise ratio is on the order of 30 Db or better. The algorithm has been tested over a variety of recording conditions and for a large number of speakers and has been found to perform reasonably well across all tested conditions.