The National Institutes of Health Consensus Development Conference on Helicobacter pylori in Peptic Ulcer Disease brought together specialists in gastroenterology, surgery, infectious diseases, epidemiology, and pathology, as well as the public, to address the following questions: (1) What is the causal relationship of H. pylori to upper gastrointestinal disease? (2) How does one diagnose and eradicate H. pylori infection? (3) Does eradication of H. pylori infection benefit the patient with peptic ulcer disease? (4) What is the relationship between H. pylori infection and gastric malignancy? (5) Which H. pylori-infected patients should be treated? (6) What are the most important questions that must be addressed by future research in H. pylori infections? Following 1 1/2 days of presentations by experts and discussion by the audience, a consensus panel weighed the evidence and prepared their consensus statement. Among their findings, the consensus panel concluded that: (1) ulcer patients with H. pylori infection require treatment with antimicrobial agents in addition to antisecretory drugs whether on first presentation with the illness or on recurrence; (2) the value of treating non-ulcer dyspepsia patients with H. pylori infection remains to be determined; and (3) the interesting relationship between H. pylori infection and gastric cancers requires further exploration. The full text of the consensus panel's statement follows.