This article analyses the principles of selecting lexical and phraseological units for a lexical minimum in teaching Russian as a foreign language to Polish-speaking learners. The study applies a comparative approach combined with elements of corpus-based and language teaching analysis. Normative and authorial lexical minima as well as data on lexical coverage and interlingual interference are examined. The results indicate the significant role of similarities between Slavic languages, which facilitate positive transfer but at the same time generate difficulties related to interference and the illusion of comprehension. The findings point to the need to modify existing lexical minima by taking into account the learners’ native language, the currency of vocabulary, and its communicative value. The conclusion emphasizes the necessity of developing adaptive, thematically diversified, and functionally structured lexical minima that support the development of communicative competence.