A facile microwave-assisted synthetic route has been successfully developed to prepare CuO microspheres in the presence of poly(vinylpyrrolidone) (PVP). The products were characterized by X-ray diffraction and scanning electron microscopy. The effects of microwave irradiation time and surfactant on the morphologies of the resulting products were investigated. Gas-sensing tests demonstrated that the sensors based on the CuO microspheres show higher responses to ethanol and methanol.