We studied the prevalence of polymorphisms in genes XRCC2 and XRCC3 in stomach cancer patients who lived in North Eastern Turkey. A total of 61 cancer patients and 78 controls were included in this study. Single nucleotide changes were studied in XRCC2 and XRCC3 genes at locus Arg188His and Th r241Met. Blood samples were taken from the patients and controls, and DNA was isolated. Th e regions of interest were amplifi ed using a polymerase chain reaction method. After amplifi cation, we used restriction enzymes (HphI and NcoI) to digest the amplifi ed product. Digested product was then run through gel electrophoresis. We identifi ed changes in the nucleotides in these specifi c regions. It was found that the Arg188His polymorphism of the XRCC2 gene was about 39 (24 out of the 61) among cancer patients. However, only 15 (12 out of 78) of the control group indicated this polymorphism. We also observed that 18 of the 61 cancer patients (29) carried the Th r241Met polymorphism of the XRCC3 gene whereas 11 of the 78 (14) individuals in the control group had the polymorphism. Our results showed a signifi cant diff erence in polymorphism ratios between the cancer patients and health control group for the regions of interest. Th is result clearly showed that these polymorphisms increase the risk of stomach cancer and might be a strong marker for early diagnosis of gastric cancer.