Hollow cadmium molybdate microspheres have been successfully prepared via a template-free aqueous solution method with the assistance of NaCl at room temperature. The structure and morphology of the CdMoO4 hollow microspheres were characterized by X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The microspheres have diameters of 3-6 mu m and hollow interiors of 2-3 mu m. The shell is composed of numerous single-crystalline nanorods with diameters of 30-120 nm and lengths of 1-2 mu m which are radially oriented to the center. A certain concentration of NaCl plays a key important role in the formation process of hollow microspheres, which might provide a suitable chemical environment to favor the formation of hollow CdMoO4 microspheres. A possible NaCl-induced Ostwald ripening process is proposed for the formation of hollow CdMoO4 microspheres on the basis of scanning electron microscopy observation of intermediate products at different precipitation stages.