abstract the present study is concerned with the syntactic deviation in hafezs poetry. poems are known to be accompanied with various linguistic deviations. these deviations may be phonological, morphological and/or syntactic. the relatively high frequency of the cases of the syntactic deviation in hafezs poems makes this rhetorical feature as a main characteristic of his poetry. this thesis, therefore, aims at exploring the different syntactic deviations hafez had used in construction of the sentences. in order to achieve this objective, we first review the theoretical background of works, conducted either in west or iran, with regard to the issues of language and speech, linguistic sign, syntagmatic and paradigmatic relations and synchronic and diachronic studies. considering the figures of speech, we then define the notions of literary norm, linguistic gauge, language variations and standard variation. we also take into consideration the six functions of language, i.e., emotive, conative referential, metalinguistic, phatic and literature, introduced by jackubson. examining about 400 verses from divan-e hafez, we found that the deviations hafez made in the syntactic structure of his poems were mostly in the forms of, change, deletion and addition of the sentences constituents. we also concluded that hafez consciously deviated from the normal structure of the sentences. in this way not only did not he violate grammatical rules of persian sentences, but he increased the aesthetic