Chickpea is commonly grown in large scales in the western part of Iran (Kermanshah, Hamedan, Lorestan and Chahar Mahal & Bakhtiari) and it forms a symbiotic relationship with rhizobia which promotes legumes growth through nitrogenfixation. Therefore, it is important to evaluate the population genetic structure of rhizobia nodulating chickpea in various areas to manage extension of chickpea cultivation. In this study, the characterization of chickpea nodulating rhizobia was carried out by PCR-RFLP analysis and nucleotide sequence determination of 16S rDNA region in addition to tracking and sequencing of nodC and nifH genes, which directly affected on Rhizobium- legume symbiosis. The results indicated that the diversity of rhizobia isolated from chickpeas in different sites is limited and they mainly belonged to Mesorhizobium cicer. Few strains of Agrobacrium tumefaciens were isolated from root nodules of chickpea growing in Lorestan soils indicating the absence of nodC and nifH genes in these isolates raising doubt about their nitrogen fixation capability. It seems that the long history of chickpea cultivation in western provinces and the specific relationship of chickpea with its symbionats are the main factors in predominance of M. cicer and absence of other Misorhizobium sp. in symbiosis with chickpea in Iran.