Thus, the aim of this study was to evaluate whether NOS2 polymorphisms Ser608Leu in exon 16 and -954G/C and -1173C/T, both in the promoter region, are associated with risk of chronic gastritis and gastric cancer in a Brazilian population and whether there is an association of cancer with risk factors such as smoking, alcohol intake and H. pylori infection. The gene discussed is NOS2; the disease is chronic gastritis.