A new approach for deriving the temperature distribution in biological tissues of microwave radiometry is proposed. It consists in the measurement of the thermal radiation of the body, at a given frequency, as a function of the observation angle, for two mutually orthogonal polarizations. Theoretically, this method yields results comparable to those obtained with the multispectral method. In order to derive the relations between the body temperature and the emitted thermal signal, the biological body is modeled by a set of parallel planar layers, each characterized by constant permittivity and temperature. It is demonstrated that for all practical purposes the radiation pattern of the antenna may be approximated by that of an unbounded plane wave.