ZnS–TiO₂ hetero-nanostructured photocatalysts were synthesized by the impregnation of ZnS quantum dots (QDs) on the surface of TiO₂ nanofibers. Samples were characterized by X-ray diffraction (XRD), field emission gun scanning electron microscopy (FEG-SEM), X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance spectroscopy. The photocatalytic activity of the prepared nanostructures was assessed by the photodegradation of methylene blue in an aqueous solution under UV irradiation. It was found that titanium dioxide impregnated with ZnS QDs increased photocatalytic activity. We demonstrated that methylene blue was more efficiently photodegraded by UV irradiation using ZnS-TiO₂ heterogeneous photocatalysts than using pristine TiO₂ nanofibers.