The results of previous studies showed a possibility of application of zero-crossing rates as parameters for speech and speaker recognition The paper presents a method for obtaining these parameters and the results of experiments carried out in order to estimate the absolute and relative discriminating power of zero-crossing parameters in speech and speaker recognition. As a basic test material 6 repetitions of 6 Polish vowels produced by 6 speakers were used. The results of the experiments utilizing the distribution of time intervals between the zero-crossings of the speech signal indicate a good effectiveness of these parameters both for speech and speaker recognition.