Different virulence factors are involved in Helicobacter pylori pathogenesis. H. pylori outer membrane proteins are a family of virulence factors that have diverse members. HopQ (H. pylori outer membrane protein) is the largest of them that contains types I and II alleles. The role of hopQ is not exactly known, but it has been considered in H. pylori adhesion and colonization. The aim of this study was to determine the frequency of hopQ genotypes among H. pylori isolates obtained from patients with gastroduodenal disorders and their association with the clinical outcome. The DNA of 100 H. pylori clinical isolates was investigated by polymerase chain reaction (PCR) method using specific primers for determining the hopQI and hopQII genotypes. hopQI was present in 35%, while hopQII was positive in 55% of the isolates. Amongst the gastritis subjects, the rate of hopQII compared to hopQI was higher, and a statistically significant difference was found between hopQII genotype and the clinical outcome. With respect to the significant difference between the hopQ genotype and clinical outcome in our clinical isolates, it seems that this genotype is a useful marker for evaluating its association with H. pylori-related diseases.