Background. Russian-Ukrainian dictionaries of the 1920s as the most common type of dictionaries of that time have left a significant mark in the history of Ukrainian lexicography. A special place among them belongs to the Russian-Ukrainian Academic Dictionary by A. Krymskyi and S. Yefremov. The study of this and other Russian-Ukrainian dictionaries, in particular the analysis of the sources of lemma lists, will allow to supplement the history of the development of Ukrainian lexicography, its formation and normalization in the 20th century.The purpose is to analyze the sources of the lemma lists and their processing in the Russian-Ukrainian dictionaries of the 1920s, in particular in the Academic Russian-Ukrainian Dictionary by A. Krymskyi and S. Yefremov.Methods. The main method of our study is descriptive with the elements of the comparative analysis, which has made it possible to identify the common and excellent in the selection and processing of the source database of the lemma lists of Russian-Ukrainian dictionaries, in particular, the RussianUkrainian Academic Dictionary.Results. Sources of lemma lists of Russian-Ukrainian dictionaries of the 1920s mainly were dictionaries of the previous years, among which were bilingual, stylistic, spelling, terminological, and explanatory. Some materials from the press were also involved. The lemma list of the Academic RussianUkrainian Dictionary by A. Krymskyi and S. Yefremov was also based on three bilingual and two explanatory dictionaries.Discussion. The lemma list of the academic Russian-Ukrainian dictionary by A. Krymskyi and S. Yefremov was compiled on the basis of bilingual and explanatory dictionaries of previous years. Scientific, fiction and press materials were not involved. Compared to source dictionaries, academic dictionary was partially supplemented and updated. In particular, in the lemma list homonyms, derivative names and adjectives were segregated, some (mostly obsolete) variants of the words were excluded, more synonyms and diminutives were included.Article received 19.04.2018

У статті описано джерела реєстру російсько-українського академічного словника за редакцією А. Кримського та С. Єфремова, а також інших російсько-українських словників 20-х рр. ХХ ст. Реєстри тогочасних перекладних словників базувалися переважно на реєстрах перекладних словників, виданих раніше, частково залучалися словники інших типів, зокрема термінологічні, а також матеріали преси.Матеріал надійшов 19.04.2018