We present the results of stratospheric and mesospheric ozone observations at the millimeter wavelengths. It is shown that the microwave remote sensing methods are important for studying the physical and chemical processes which play a significant role in the ozone-layer depletion. Examples of the results of ozone observations at 142.2 GHz by the spectrometer of the P. N. Lebedev Physical Institute of the Russian Academy of Sciences (LPI RAS) illustrate the high efficiency of radiophysical techniques for atmospheric-ozone research.