A low-temperature template-free two-step aqueous solution route has been successfully developed to prepare ZnO nanobrushes. First, hexagonal ZnO microrods were grown from the precursor solutions containing zinc nitrate hexahydrate and hexamethylenetetramine. In the second step, well-aligned vertical ZnO nanorods were grown particularly on the facet planes of hexagonal ZnO microrods from the precursor solutions of zinc nitrate hexahydrate and NH(4)OH. This two-step aqueous process consequently produces ZnO nanostructures with a nanobrush shape. Structure and morphology of the synthesized ZnO nanobrushes were investigated by using X-ray diffraction, field-emission scanning electron microscopy, and photoluminescence.