This study aimed to evaluate the antifungal potential of the essential oil (EO) from Hesperozygis ringens leaves and its major compound pulegone against wood-decay fungi. In addition, their effect on mycelia ergosterol content was assayed. The EO was extracted by hydrodistillation and its chemical composition was analyzed by gas chromatography coupled to mass spectrometry and gas chromatography with flame ionization detector. Pulegone was isolated through column chromatography. The EO and pulegone were tested on white-rot fungi (Ganoderma applanatum and Trametes versicolor), and brown-rot fungi (Gloeophyllum trabeum and Lentinus lepideus) in five and three concentrations, respectively. Propiconazole was used as positive control. The EO inhibited T. versicolor growth while pulegone inhibited growth of both white-rot species. Pulegone presented lower half-maximal inhibitory concentration than the EO for white-rot fungi. Both EO and pulegone negatively affected white-rot fungi ergosterol contents. White-rot fungi, in general, were more susceptible to EO and pulegone.