Helicobacter pylori (H. pylori) infection causes chronic gastritis, peptic ulcers, gastric adenocarcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma. Bacterial, host, and environmental factors influence the progression of disease from superficial gastritis to cancer. H. pylori is genetically diverse, and expression of its specific virulence factors has been linked to increased risk of more severe pathologies. Described in this chapter is a protocol for detecting important H. pylori virulence factors by firstly extracting DNA from culture material or stomach tissue biopsies, followed by PCR amplification and agarose gel electrophoresis.