Background: Heyde syndrome, a triad of aortic stenosis, von Willebrand factor deficiency, and gastrointestinal (GI) bleeding from angiodysplasia, is a disease of the elderly. A Dieulafoy lesion, a specific type of angiodysplasia, is a large, tortuous, submucosal end artery that penetrates through the gastric mucosa and can cause life-threatening GI bleeding. We present a case of Heyde syndrome complicated by a Dieulafoy lesion.; Case Report: A 72-year-old female presented with GI bleeding evidenced by black tarry stool for 7 days. Hemoglobin (Hgb) level was as low as 6.0 g/dL. Double-balloon enteroscopy (DBE) revealed 2 jejunal angiodysplasias that were treated with argon plasma coagulation. The patient continued to have dark stools after discharge. Repeat complete blood count showed Hgb of 6.2 g/dL, and repeat DBE showed a 1-mm focus of active bleeding in the proximal jejunum consistent with a Dieulafoy lesion. The lesion was successfully treated with argon plasma at 1 L/min and 25 watts. At follow-up 1 year later, the patient had had no GI bleeding symptoms since discharge.; Conclusion: This case adds evidence that a Dieulafoy lesion is a potential complication of Heyde syndrome. Dieulafoy lesions can be life-threatening, so documenting occurrences that are complications of Heyde syndrome is important because of the potential for an increasing incidence of Heyde syndrome in the aging population.