The prevalence of Helicobacter pylori in patients with upper gastrointestinal symptoms in the north of Jordan was studied prospectively. The occurrence of H. pylori was documented histologically and bacteriologically in 169 patients attending endoscopy for upper gastrointestinal symptoms. Our results showed that H. pylori was present in 70% of patients with acute gastritis, 73% of patients with chronic gastritis, 68% of patients with acute on chronic gastritis, 83% of patients with duodenal ulceration, 75% of the patients with gastric ulceration, 64% of patients with no pathology, and 68% of patients regardless of the pathology found. There was a sharp rise in the prevalence of H. pylori with age, up to the age of 40 years with an annual increase in the prevalence of 2%. This study shows that the prevalence of H. pylori in Jordan is similar to that seen in other developing countries with infections occurring at a lower age and with the annual infection rate being double that seen in developed countries.