BACKGROUND Upper gastrointestinal endoscopy has been reported as a risk factor for the transmission of Helicobacter pylori. The aim of this study was to evaluate the possibility of transmission of H. pylori infection by upper gastrointestinal endoscopy in patients who had previously had such procedures in a low disinfection level environment. METHODS The study included 1082 patients. Patients that had undergone upper gastrointestinal endoscopy or were treated with antibiotics 15 days before the index endoscopy were excluded. H. pylori infection was diagnosed by ultra-rapid urease test. Variables analyzed were age, gender, type of dyspepsia (organic or functional), and the number of previous upper gastrointestinal endoscopies. RESULTS Overall prevalence of H. pylori infection was 60%. Patients ranged in age from 13 to 94 years (mean = 45.8, SD = 15.7) and the number of previous upper gastrointestinal endoscopies ranged from 0 to 20 (mean = 1.5, SD = 2.4). In 53.3% of the patients, upper gastrointestinal endoscopy revealed some mucosal lesion (organic dyspepsia). Prevalence of H. pylori infection was higher in patients with organic rather than functional dyspepsia (71.1% vs. 47.1%, p < 0.001). There was no statistically significant difference in the mean number of upper gastrointestinal endoscopies in patients with and without H. pylori infection. CONCLUSIONS We concluded that there was no association between history of upper gastrointestinal endoscopy and current H. pylori infection in this study population.