It is well-known that both Russian and Farsi languages typologically belong to the same family. They have many common features in morphological and syntactic structure point of view. The Complement, as a part of a sentence, is a syntactic subject, which is studied in both languages. Taking a general definition of the complement, as a word which adds some meanings to the another word, one can determine attribute, adverbial modifier, and appositive as the complement in the structure of Russian sentences. In the present paper the essence of the complement and their types in the Russian grammar, compared to Persian language, is investigated