Human mycoses have controversial treatment, since the available antifungal drugs besides favoring the appearance of resistant isolates, can present great toxicity to the human organism. This fact has driven the search for more efficient, safe and natural therapeutic alternatives with the objective of reversing this scenario of resistance presented by pathogenic fungi, for this, new natural and effective alternatives, such as the use of plant extracts, natural compounds and semi-synthetic, have been extensively investigated for the development of new drugs. In view of this scenario, this study aims to evaluate the antifungal activity of isoeugenol in vitro against strains of Penicillium citrinum. For this, the broth microdilution technique was used to determine the Minimum Inhibitory Concentration (MIC) and Minimum Fungicide Concentration (MFC) of isoeugenol and voriconazole. The concentrations by which the strains were submitted, 1024 μg/mL to 0.5 μg/mL, were obtained by means of serial dilution at a ratio of two, so that in the first row of the plate is the highest concentration and in the last , the lowest concentration. Finally, 10 μL of the fungal inoculum of each isolate was added to the wells, where each strain was placed on a plate column. MIC was defined as the lowest concentration capable of inhibiting fungal growth visually verified by maintaining the original coloration of the medium. After reading the MIC, aliquots of 20 μL of the supernatant from the wells where complete inhibition of fungal growth in the microdilution plates were observed were plated on Sabouraud dextrose agar plates. Plates were incubated, and MFC was considered the lowest concentration at which growth was less than 3 colonies. The assays were performed in triplicate and the geometric mean was calculated. The CIM of isoeugenol varied between 256 and 32 μg/mL, being the highest MIC value for the LM-21 strain and the lowest value for the LM-02, LM-03, LM-08, LM-155, LM- 157 and LM-161. The MIC range of voriconazole was 0.5 to 256 μg/mL. The MFC of isoeugenol varied between 64-512 μg/mL and for voriconazole it was 2 μg/mL and above 1024 μg/mL. In this way, we can conclude that isoeugenol presented an antifungal effect, which enables it as a potential antifungal drug, requiring complementary tests that clarify the mechanism of action involved in its antimicrobial activity.