Tubers such as cassava (Mandioca spp.) and yam (Dioscorea spp.) are sensitive to fungal deterioration, affecting their production and marketing. This has generated the need to develop treatments that minimize damage in the post-harvest stage. This research evaluated the in vitro inhibitory capacity of chitosan- and oregano essential oil (OEO) (Origanum vulgaris)-based coatings against the fungus P. brevicompactum due to their antifungal, antimicrobial, and anti-inflammatory properties. For this purpose, tests were performed to find the minimum inhibitory concentration (MIC) corresponding to 0.1562 µL/mL, which decreased the growth rate of the microorganism dependent on the OEO concentration. When using sublethal concentrations of OEO, an inhibition percentage of 82.5% ± 1% was obtained at a concentration of 0.0781 µL/mL. The kinetic analysis parameters for the fungal growth were estimated from the modified Gompertz model A (maximum diameter reached by the colony during stationary phase), ?m (maximum growth rate), and λ (lag phase duration) for both the control and the treatments. In addition, a hypothesis test for media comparison of growth intervals was performed, resulting in A: 2.5768, ?m:0.325762, and λ:0.20962 for controls, and A: 1.033289, ?m:0.49902, and λ:5.73742 for treatments, giving a significant difference within a 95% confidence interval. Morphological changes in the cellular structure of the fungus could be observed by optical microscopy, noting a considerable increase in the permeability of the plasma membrane. Likewise, morphological changes in the structure of the mycelium were noted. The results of this research allow for the visualization ofchitosan- and OEO-based coatings as a sustainable alternative for the post-harvest preservation of tubers such as cassava and yam.