Novel hierarchical heterostructures formed by wrapping ZnS nanowires with highly dense SiO2 nanowireswere successfully synthesized by a vapor−liquid−solid process. The as-synthesized products were characterizedusing X-ray diffraction, scanning electron microscopy and transmission electron microscopy equipped withan energy-dispersive X-ray spectrometer. Studies indicate that a typical hierarchical ZnS/SiO2 heterostructureconsists of a single-crystalline ZnS nanowire (core) with diameter gradually decreasing from several hundrednanometers to 20 nm and adjacent amorphous SiO2 nanowires (branches) with diameters of about 20 nm. Apossible growth mechanism was also proposed for the growth of the hierarchical heterostructures.