Helicobacter pylori is possibly the most common bacterial infection of humans and is now recognized as the most important acquired cause of peptic ulceration. Epidemiological evidence also recently implicated this bacterium in the pathogenesis of gastric cancer. The mechanism of spread of the organism, by either the faecal-oral or oral-oral route, raises the possibility of transmission of this organism from infected patients to hospital staff particularly those involved in endoscopy. The evidence for an increased risk to endoscopists is contradictory, varying from none to a five-fold increase. This review summarizes the evidence for mode of transmission and risk to hospital staff from this important bacterium.