Abstract Crohn’s disease (CD) may affect the entire gastrointestinal tract including its upper part. However, this aspect is poorly addressed in scientific literature and considered a rare finding. Here we aimed to prospectively investigate the prevalence, characteristics and clinical significance of upper gastrointestinal tract involvement in patients with CD, with particular focus on stomach bamboo joint-like appearance (BJA), Helicobacter pylori status and presence of microscopic changes. 375 prospectively recruited patients were included. In CD patients the prevalence of gastric and duodenal, but not esophageal, mucosal lesions, such as gastric mucosal inflammation, duodenal edema, ulcerations, and duodenal bulb deformation was significantly higher (at least p