Background & aims: Iron deficiency anemia is a common complication of gastric surgery that in certain patients can be refractory to treatment with oral iron and needs to be treated parenterally. Methods: A 48-year woman underwent gastric surgery for a gastric ulcer. She was referred to the nutrition unit for the study and treatment of a 3-year iron deficiency anemia refractory to oral iron supplementation. Blood tests, endoscopy and jejunal biopsy were made to study the case. Results: Intestinal villi atrophy in the absence of celiac disease was the result. She was treated with intravenous iron, resolving the villous atrophy and thus oral iron supplementation could be effective. Conclusion: This case illustrates that iron deficiency may cause villous atrophy. In this setting, parenteral iron administration is necessary to correct the haematological and non-hematological alterations associated with this deficiency.