The contamination of endoscopes and biopsy forceps with Helicobacter pylori occurs readily after endoscopic examination of H. pylori-positive patients. Unequivocal proof of iatrogenic transmission of the organism has been provided. Estimates for transmission frequency approximate to 4 per 1000 endoscopies when the infection rate in the endoscoped population is about 60%. Iatrogenic transmission has also been shown to be the cause of the so-called 'acute mucosal lesion' syndrome in Japan. Traditional cleaning and alcohol rinsing is insufficient to eliminate endoscope/forceps contamination. Only meticulous adherence to disinfection recommendations guarantees H. pylori elimination.