Rather intense spectral lines of HDO molecule have been detected in the emission spectra of the atmosphere observed from space by the IMG sensor in the region 650-2000 cm-1 with the resolution of 0.1 cm-1. The analysis of signals from the isotopic species of the water molecule suggests the possibility of their use for determination of the HDO/H2O concentration ratio in the atmosphere. As an example of application of the proposed method, the results of IMG/ADEOS data processing at some observation points of the atmosphere over the ocean and land in tropical and middle latitudes under clear sky conditions are presented.