Identification of resistant sources to Ascochyta blight (AB) has been considered as a main purpose in most chickpea breeding programs. Achievements to molecular markers related to resistance to Ascochyta rabiei allows selection programs to be developed more accurately and efficiently. The aim of this study was to investigate the applicability of a functional SNP in differentiating Iranian resistant cultivars to be used in selection programs. Amplification of SNP-containing fragment with specific primer pair and its sequencing resulted in tracking and determining the allelic pattern of SNP18, SNP18-2147, SNP18-2491 and SNP18-2554 loci belong to GSH118 gene in ILC263 (sensitive) and MCC133 (resistant) chickpea lines. Mutations in SNP18 and SNP18-2147 occur at the protein level at positions 499 and 554. Bioinformatics studies have shown that the GSH118 gene is a Lucien-rich repeat receptor kinases (LRR-RKs) and encodes a membrane protein which can be involved in recognizing microorganisms and initiating immune signaling pathways in plants. Additional studies to determine the function of this gene and its interaction with other proteins can be effective in gaining more knowledge about the molecular basis of resistance against AB.