The article deals with the manuscript of a two-volume Russian-Belarusian Dictionary, prepared by the Institute of Linguistics of the Belarusian Academy of Sciences in the 1930s. There remained some fragments of the dictionary (more than 11.000 entries; while the real number of entries could probably total 100.000) in the archival funds of the bureau of the Central Committee of the Communist Party of Belarus in the State Archive of the Republic of Belarus. Compared with the Russian-Belarusian Dictionary by M. Bajkou and S. Niekraševič (1928) the set of Belarusian equivalents to Russian words was greatly curtailed in this dictionary (dated 1936). In many cases Russicisms or lexemes that formally coincided with those of Russian were included in the Belarusian part of the dictionary. The abridgement of the word-list for ideological and puristic reasons was one of the important aspects of work on the manuscript.