AbstractObjective:To introduce pseudoaneurysm of the sphenopalatine artery as the possible aetiology of acute massive epistaxis in patients with a history of orthognathic surgery accompanied by Le Fort I osteotomy.Methods:Case report and literature review.Results:This paper reports a case of acute life-threatening epistaxis following Le Fort I osteotomy. Computed tomography and angiography showed a pseudoaneurysm of the sphenopalatine artery, which was successfully treated by endovascular embolisation.Conclusion:Although a pseudoaneurysm of the sphenopalatine artery following Le Fort I osteotomy is extremely rare, it should be considered as the possible aetiology of acute massive epistaxis in patients with a history of orthognathic surgery accompanied by Le Fort I osteotomy.