Upper gastrointestinal endoscopy and radiologic examination were performed in 101 patients with symptoms strongly suggestive of gastroesophageal reflux (GER) disease. Hiatus hernia (HH) was found in 50 patients diagnosed by radiography or endoscopy, or both, in 22, 19, and 9 patients respectively. Severe endoscopic esophagitis (grades III and IV) was found more often (p less than 0.05) in the patients with HH than in those without. The same was true for the early positive timed acid perfusion tests (p less than 0.02). Furthermore, the patients with HH more often had reflux by the standard acid reflux test (42 of 50 versus 28 of 51; p less than 0.01), gastroesophageal scintigraphy (47 of 50 versus 40 of 51; p less than 0.05), and radiography (20 of 50 versus 2 of 51; p less than 0.001) than the patients without HH. The results show that severe GER disease can occur without an associated HH and indicate that patients with symptoms of GER disease and associated HH are likely to have a more severe GER disease than those without HH.