A 68-year-old woman with iron deficiency anemia (due to gastrointestinal bleeding) was evaluated. Over a period of two years she received iron supplementation perorally and intravenously, as well as multiple blood transfusions, but the hemoglobin level did not exceed 10 g/dL. The investigations included upper endoscopy, duodenoscopy with side optical view, ileocolonoscopy, capsule endoscopy, antegrad single-balloon enteroscopy and conventional angiography of the abdominal vessels. Upper and lower endoscopies were performed repeatedly. The only consistent finding was linear erosions of the gastric mucosa in a large hiatal hernia at the level of the diaphragm. The association between large hiatal hernias and iron deficiency anemia was first described in the 1930s. The bleeding source is thought to be erosions or ulcerations in the hiatal hernia, as described by Cameron & Higgins in 1986. These lesions are analogous to the finding in our patient. The recognized treatment options are iron supplementation, proton pump inhibition and fundoplication. In our case we decided to start treatment with pantoprazole. Her hemoglobin level had normalized within an observational period of three months.