The invention relates to stable compositions for providing PVC with fungicidal properties. Said stable compositions contain at least one thiabendazole as an active substance, at least one plasticizer for PVC, at least one thixotropic agent, and, optionally, other fungicidal agents. The invention also relates to methods for producing said formulations and the uses thereof for preventing PVC from being infested and destroyed by microorganisms. The invention further relates to mildew-resistant PVC materials provided with the compositions of the invention.
