Abstract Background: Genes of helicobacter pylori produce copious amounts of ammonia which is among the leading precipitating factors of hepatic encephalopathy. Aim of Study: To study the impact of H. pylori infection and its associated genes on the occurrence and severity of hepatic encephalopathy. Patients and Methods: This study included 100 patients with liver cirrhosis and H. pylori infection in addition to 20 H. pylori infected subjects without liver cirrhosis serving as a control group. All of them were subjected to: Rapid urease test, measuring serum ammonia level, and gene expression (vacA, ureA/ureB, ureI, amiE/amiF, rocFand nixA) by RNA extraction. Results: Serum ammonia level was higher when UreI, Ami E, Ami F and Roc F genes were expressed while it was lower when Nix A and Vac A genes were expressed in some of the studied groups. As regards Nix A gene, serum ammonia level was significantly higher when the gene expressed among cirrhotic patients without hepatic encephalopathy (p-value =0.017). Conclusions: Our data showed that despite serum ammonia was significantly higher among the cirrhotic patients with hepatic encephalopathy did not show a significant relation with different grades of hepatic encephalopathy. Also no statistical significant relation was found between serum ammonia and H. pylori genes expression.