The aim of the present study was to analyse the adequacy of hearing protection devices (HPDs) by applying and comparing different methods for the estimation of effective exposure levels. This comparison involved the attenuation data of 50 HPDs (ear muffs and ear plugs), as well as 11 types of noise spectra and 4 methods. The application of the several methods considered and the comparison of the obtained estimations seem to demonstrate that there are significant differences between effective exposure levels estimated with the different methods analysed.