A chemosensitive single nucleotide polymorphism (SNP) discovery schema is presented that utilizes (i) genome-wide SNP screening, with a human SNP array and an in vitro chemosensitivity assay, in 93 patients with gastric cancer (GC), and (ii) biological utility assessment using cell viability assays of transfected GC cells. Cytotoxicity analysis showed that most of the MKN1 and SNU638 clones transfected with the G allele of Deoxyribonuclease II beta (DNASE2B) rs3738573 were more sensitive to docetaxel than those with the C allele (p≤0.001-0.029) and most of the AGS and SNU638 clones transfected with the T allele of 5-hydroxytryptamine receptor IE (HTRIE) rs3828741 were more sensitive to paclitaxel than those with the C allele (p≤0.001-0.019). Our findings show that the two novel markers, DNASE2B rs3738573 and HTR1E rs3828741, have potential for improving the prediction of chemosensitivity of GC patients.