BACKGROUND: Upper gastrointestinal diseases are relatively important in Korea. There are various studies on upper gastrointestinal diseases, especially relationships with Helicobacter pylori, but studies on young adults are relatively fewer. Therefore, we conducted this study in order to know the prevalence of various upper gastrointestinal diseases and the association with Helicobacter pylori among young policemen. METHODS: Diagnosis and classification of upper gastrointestinal diseases were made 260 policemen, who visited the outpatient department of family medicine at one general hospital in Seoul from March 2, 2001 to December 31, 2002. RESULTS: The frequencies of upper gastrointestinal diseases were gastritis (62.2%), duodenal ulcer (14.4%), gastric ulcer (7.5%), duodenitis (6.9%), and no active lesion (9.0%). The frequency of multiple upper gastrointestinal disease was chronic superficial gastritis and duodenal ulcer (37%), chronic superficial gastritis and duodenitis (21.9%), and acute gastritis and duodenal ulcer (16.4%), and these groups comprised the most with 75.3%. The location of the lesion was found at antrum (62.2%) and duodenum (21.6%). Ulcer stages in gastric and duodenal ulcer were mostly in active stage. Helicobacter pylori infection in gastric and duodenal ulcer were 36% and 85.4%, respectively. CONCLUSION: Most symptomatic patients had lesions which were found at antrum and duodenum as in other studies. Ulcer diseases in duodenum were much more frequent than those in stomach, which probably be associated with Helicobacter pylori. Therefore, suitable examination and treatment are necessary.