The objective of this study was to examine the association between the XRCC1 A910G polymorphism in gastric cancer patients in the city of Macapá, State of Amapá, Amazonia, Brazil. DNA samples were obtained from 102 individuals, of which 40 were cancer patients and 62 controls. Polymerase Chain Reaction (PCR) was carried out to detect polymorphism, followed by PCR-RFLP analysis with the restriction enzyme HhaI. Of the 40 patients analysed, 22.5% had the Thr910Thr (A/A) genotype, while Ala910Ala (G/G) and Thr910Ala (A/G) genotypes accounted for 25% and 52.5% of samples, respectively. In the control group, of the 62 samples analysed, 74.1% had the Thr910Thr (A/A) genotype, while Ala910Ala (G/G) and Thr910Ala (A/G) represented 9.6% and 16.1% of samples, respectively. Our findings demonstrate that A910G polymorphism was found in most of the patients with gastric cancer in the study population. The G allele was frequently found in the analysed samples, as also observed in the genotype frequency, where AG and GG genotypes were present in cancer patients. This is the first study in Brazil to report the association between A910G polymorphism and gastric cancer.