Abstract <p>The paper presents a new method of emission spectroscopy in the far infrared range. This method does not require heating or other excitation of the sample; that is, it allows recording the spectrum of intrinsic radiation. The spectra of lactose monohydrate, liquid water, and water vapor were recorded at room temperature. Emission bands corresponding to phonon vibrations of the crystal lattice of lactose monohydrate and rotational transitions of water molecules in the gas phase are recorded. For liquid water, the emission spectrum was recorded in the range of 7–200 cm^–1, and the potential for extension to the mid-infrared range was noted. A method has been developed for expressing the spectra of intrinsic radiation in absolute units of spectral radiosity. Spectroscopy of intrinsic radiation is as informative as absorption spectroscopy and does not require the use of a radiation source. This may be especially in demand for spectral analysis of radiation-sensitive samples.</p>