The existing synthesis methods to hollow nanostructures of inorganic materials often demand the assistance of extra templates, catalysts, surfactants, etc., which undoubtedly cause a higher cost and a more complex purification procedure, or even worse, a higher level of pollution to both the product and the environment. In this letter, we report a novel solvothermal synthesis of two different hollow nanostructures of semiconducting CdO from an easily obtained inorganic single-source precursor, CdO 2 nanoparticles with the average size of about 5 nm. Without the use of any extra template, catalyst and surfactant, hollow quasi-spherical and irregular bamboo-like nanostructures of CdO were synthesized simply via mild (180 °C, 24 h) solvothermal treatment of the CdO 2 nanoparticles in ethanol and ethylene glycol, respectively. The resultant products were characterized by powder X-ray diffraction (XRD), transmission electronic microscope (TEM) and UV–vis absorption spectra, and their possible formation mechanisms were also tentatively proposed.