Atactic polystyrene, one of the most widely used chemical products, was subjected to novel chemically oxidative treatments able to trigger a great variety of physical and chemical changes in the polymer's chains. The oxidized polystyrene samples, when analyzed with Fourier transform infrared spectroscopy (FTIR) clearly showed the formation of carbonyl groups and hydroxyl groups, which increased with the increase in the strength of chemically oxidative treatments. In fungal degradation tests deploying Curvularia species, the fungus colonized the oxidized samples within 9 weeks. Colonization was confirmed by microscopic examination, which showed that the hyphae had adhered to and penetrated the polymer's structure in all the treated samples. Such colonization and adhesion by microorganisms are a fundamental prerequisite for biodegradation of polymers.