Brown planthopper (BPH) is a destructive insect pest of rice in Korea. Identification and the incorporation of newBPH resistance genes into modern rice cultivars are important breeding strategies to control the damage caused by BPH. To expand genetic resource against BPH in Korea, we screened more than 2,500 mutant lines, which were derived from EMS treatment on Namil, a high yielding Korean japonica cultivar. One mutant line, Namil(EMS)M2-1463-1-1-1-1, designated as ‘Namil(EMS)-bl10,bph1’ performed high level of resistance against BPGH and rice blast, while the wild type, Namil, performed highly susceptible to rice blast as well as BPH. A mapping population was constructed by using F2 progeny lines derived from cross between Namil(EMS)-bl10,bph1 and Milyang23, a BPH susceptible Tongil type cultivar. DNAs prepared from F2 individuals were used for SSR marker based linkage map skeleton, and F2:3 seeds were subjected to BPH infestation to infer resistance level of corresponding F2 plant. Association analysis between marker genotype and evaluated survival ratio of each progeny line were used to localize the putative chromosomal location(s) involved to BPH resistance. The location was initially located on the subterminal region of the long arm of chromosome 12 flanked by the SSR markers RM1337 and RM277, where at least three BPH resistance genes, Bph1, Bph18, and Bph21, were localized previously.