The subject of this article are the nouns, adjectives, verbs and adverbs in Russian and Serbo-Croatian, motivated by nouns with agentive suffix ʻ-тельʼ. Analysis of second formations from the stems on suffix ʻ-тельʼ is made on the material of explanatory, bilingual, word-building and reverse dictionaries of Russian and Serbo-Croatian. In the comparative analysis structural similarities and differences between Russian and Serbo-Croatian forms with motivational stem on suffix ʻ-тельʼ are revealed.