The accepted paradigm for intestinal-type gastric cancer pathogenesis is a multistep progression from chronic gastritis induced by Helicobacter pylori(H. pylori) to gastric atrophy, intestinal metaplasia, dysplasia and ultimately gastric cancer. The genetic and molecular mechanisms underlying disease progression are still not completely understood as only a fraction of colonized individuals ever develop neoplasia suggesting that bacterial, host and environmental factors are involved. Micro RNAs are noncoding RNAs that may influence H. pylori-related pathology through the regulation of the transcription and expression of various genes, playing an important role in inflammation, cell proliferation, apoptosis and differentiation. Indeed, H. pylori have been shown to modify micro RNA expression in the gastric mucosa and micro RNAs are involved in the immune host response to the bacteria and in the regulation of the inflammatory response. Micro RNAs have a key role in the regulation of inflammatory pathways and H. pylori may influence inflammation-mediated gastric carcinogenesis possibly through DNA methylation and epigenetic silencing of tumor suppressor micro RNAs. Furthermore, micro RNAs influenced by H. pylori also have been found to be involved in cell cycle regulation, apoptosis and epithelial-mesenchymal transition. Altogether, micro RNAs seem to have an important role in the progression from gastritis to preneoplastic conditions and neoplastic lesions and since each micro RNA can control the expression of hundreds to thousands of genes, knowledge of micro RNAs target genes and their functions are of paramount importance. In this article we present a comprehensive review about the role of micro RNAs in H. pylori gastric carcinogenesis, identifying the micro RNAs downregulated and upregulated in the infection and clarifying their biological role in the link between immune host response, inflammation, DNA methylation and gastric carcinogenesis. The accepted paradigm for intestinal-type gastric cancer pathogenesis is a multistep progression from chronic gastritis induced by Helicobacter pylori (H. pylori) to gastric atrophy, intestinal metaplasia, dysplasia and ultimately gastric cancer. The genetic and molecular mechanisms underlying disease progression are still not completely understood as only a fraction of colonized individuals ever develop neoplasia suggesting that bacterial, host and environmental factors are involved. MicroRNAs are noncoding RNAs that may influence H. pylori-related pathology through the regulation of the transcription and expression of various genes, playing an important role in inflammation, cell proliferation, apoptosis and differentiation. Indeed, H. pylori have been shown to modify micro RNA expression in the gastric mucosa and micro RNAs are involved in the immune host response to the bacteria and in the regulation of the inflammatory response. Micro RNAs have a key role in the regulation of infl ammatory pathways and H. pylori may influence inflammation-mediated gastric carcinogenesis possibly through DNA methylation and epigenetic silencing of tumor suppressor microRNAs. Furthermore, microRNAs influenced by H. pylori also have been found to be involved in cell cycle regulation, apoptosis and epithelial -mesenchymal transition. Altogether, microRNAs seem to have an important role in the progression from gastritis to preneoplastic conditions and neoplastic lesions and since each micro RNA can control the expression of hundreds to thousands of genes, knowledge of microRNAs target genes and their functions are this paramount importance. In this article we present a comprehensive review about the role of micro RNAs in H. pylori gastric carcinogenesis, identifying the micro RNAs downregulated and upregulated in the infection and clarifying their biological role in the link between immune host response, inflammation DNA methylation and gastric carcinogenesis.