The paper discusses a retrieval technique of complex permittivity of ore minerals in frequency ranges of 12{38GHz and 77{ 145GHz. The method is based on measuring frequency dependencies of transmissivity and re∞ectivity of plate-parallel mineral samples. In the 12{38GHz range, the measurements were conducted using a panoramic standing wave ratio and attenuation meter. In the 77{145GHz range, frequency dependencies of transmissivity and re∞ectivity were obtained using millimeter-band spectrometer with backward-wave oscillators. The real and imaginary parts of complex permittivity of a mineral were determined solving an equation system for frequency dependencies of transmissivity and re∞ectivity of an absorbing layer located between two dielectric media. In the course of the work, minerals that are primary ores in iron, zinc, copper and titanium mining were investigated: magnetite, hematite, sphalerite, chalcopyrite, pyrite, and ilmenite.