Objective: To evaluate the correlation between the presence of H. pylori in paired samples of tap water and gastric cancer (GC) lesion in Lima city (Peru). Material and methods: Gastric tissue and tap-water samples were prospectively collected from 82 Gastric Cancer who lived in Lima. HspA and ureA genes were evaluated by qPCR in the samples. Results: The median age of patients with GC was 63 years, 52.4% were men and stage-II in 36.6%. A home-living time> 10 years was reported in 84.1% of patients. Boiling water treatment was indicated in 85.4% of cases. H. pylori was detected in 69.5% of gastric tissues and in 12.2% of analyzed tap-water. There was no differences in gastric infection rates among those with or without water contamination (70% vs. 69.4%, p=0.971). Conclusion & Impact: H. pylori was found in tap-water samples, however, detection rates were lower than in gastric cancer samples. Other sources of infection transmission should be investigated.