Researchers have explored natural products to combat the antibiotic resistance of various microorganisms. Cinnamaldehyde (CIN), a major component of cinnamon essential oil (CC-EO), has been found to effectively inhibit the growth of bacteria, fungi, and mildew, as well as their production of toxins. Therefore, this study aimed to create a delivery system for CIN using PLGA microparticles (CIN-MPs), and to compare the antifungal activity of the carried and free CIN, particularly against antibiotic-resistant strains of Candida spp. The first part of the study focused on synthesizing and characterizing the PLGA MPs, which had no toxic effects in vivo and produced results in line with the existing literature. The subsequent experiments analyzed the antifungal effects of MPs-CIN on Candida albicans and Candida glabrata, both resistant (R) and sensitive (S) strains and compared its efficacy with the conventional addition of free CIN to the culture medium. The results indicated that conveyed CIN increased the antifungal effects of the product, particularly towards C. albicans R. The slow and prolonged release of CIN from the PLGA MPs ensured a constant and uniform concentration of the active principle within the cells.