Little is known about the relationship between hiatus hernia (HH) and gastroesophageal reflux symptoms (GERS). Nine hundred and thirty patients submitted to gastroscopy because of symptoms completed a self-administered questionnaire. Fourteen per cent showed esophagitis (ES) and 17% HH. Forty-nine per cent of the patients with HH had endoscopic ES, and 60% of those with ES had HH. The severity of ES was dependent (p less than 0.05) on both the presence and the size of HH. After exclusion of patients with peptic ulcer and malignancy, patients with and without HH and ES were compared with regard to the presence of single symptoms and a weighted GERS score based on symptoms proven to be typical for ES. Only borderline differences were found between patients with ES and HH and those with ES and no HH. The former group, however, presented with significantly (p less than 0.001) more GERS than the patients with HH only. Nevertheless, the patients with HH as the only pathologic finding had significantly (p less than 0.01) more GERS than the patients with no major endoscopic abnormality. This study indicates a close association between HH and gastroesophageal reflux disease and supports the clinical significance of an endoscopically detected HH.