Background Previous studies have focused on the relationship between halitosis,gastroesophageal reflux disease and Helicobacter pylori.In this study we aimed to investigate the interaction between halitosis and upper gastrointestinal endoscopic findings.Methods Patients who previously had dyspepsia and had undergone endoscopic examination were included in the study.Symptoms of dyspepsia were investigated by means of a questionnaire that investigated halitosis.Patients who suffered from objective halitosis (confirmed by questions both to the patient and their relatives) were further investigated.Patients with known local or systemic causes of halitosis or structural disorders at endoscopy were excluded.Results The study included 358 patients (121 men and 237 women) with dyspeptic symptoms.The patients with and without halitosis had mean ages of (39.4+13.5) and (43.1±14.9) years,respectively.Patients without halitosis were significantly older than those in the halitosis group (P ＜0.05).Patients in the halitosis group had significantly higher frequencies of regurgitation,bloating and nausea (P ＜0.05) when compared to patients without halitosis.Endoscopic findings,including esophagitis,open cardia,hiatal hernia,gastritis and duodenitis,were comparable in the two groups.Conclusions The frequency of halitosis was high in patients with dyspepsia who underwent upper gastrointestinal endoscopy.Halitosis had a close relationship with several upper gastrointestinal symptoms,including regurgitation,nausea and bloating.There was no significant association between upper gastrointestinal endoscopic findings and halitosis.