AIM: To study whether N-acetyltransferase 2 (NAT2) genotypes and phenotypes are associated with increased risk factor for gastric cancer in Omani patients and to study the clinico-pathological correlations and the prognostic significance of NAT2.METHODS: Genomic DNA was extracted from peripheral blood of 100 gastric cancer patients and 100 control subjects. NAT2 genotyping was performed using DNA sequencing. The prognostic significance of NAT2 and other clinicopathological features was assessed by univariate and multivariate analyses.RESULTS: We observed no significant association between NAT2 genotypes and phenotypes and gastric cancer risk. The NAT2 phenotype polymorphisms and gastric cancer risk predisposition were not modified by concomitant Hpylori infection and smoking. There was no significant association between NAT2 and clinicopathological features, and NAT2 had no independent prognostic significance.CONCLUSION: In the current study, NAT2 genotypes and phenotypes are not associated with gastric cancer risk predisposition. Moreover NAT2 phenotypes had no clinicopathological associations or prognostic significance.