One of the biotic stresses in rice production is rice blast disease caused by Magnaporthe oryzae, which is one of the most destructive fungal diseases in rice. We outlined an approach towards genome wide association study for the blast disease resistance in rice. In total, 295 rice accessions including 137 Heuristic Set accessions (HS) and 158 Korean Bred varieties (KB) were screened for the rice blast disease resistance. Firstly, Magnaporthe oryzae were inoculated to the rice seedlings of two weeks after germinations. Then, evaluation of the disease symptoms and checking the crossing point (CP) value were conducted one week after inoculation. To quantify the CP value, real-time polymerase chain reaction (PCR) was employed in combination with the primer pair and Taqman probe specific to Magnaporthe oryzae HYDROPHOBIN class 1 (MHP1) which is an indispensable unigene encoding HYDROPHOBIN for normal virulence expression. Based on these CP values from the PCR reactions containing a series of increasing concentration of cloned amplicon or fungal genomic DNA, correlation among the template’s copy number or its amount and amplification pattern was calculated. Reliability of this equation was further confirmed using the DNA samples from the rice leaves infected with compatible or incompatible strains of M. oryzae. These steps are still being undertaken, and after the complete process of disease resistance phenotyping for the whole population containing 295 accessions, GWAS will be performed to examine the associated genes involving in blast resistance mechanism using the whole genome resequencing data of 295 accessions. This approach would be a useful technique for identifying genetic loci responsible for natural variation in rice blast disease resistance and ultimately, new R genes which can improve the blast resistance in rice.