INTRODUCTION: Idiopathic spontaneous intra-abdominal haemorrhage is a rare, but challenging condition, associated with high mortality if not managed appropriately. The preoperative diagnosis is difficult, despite the recent advances in imaging. We present the clinical manifestations of this condition, as well as the available diagnostic and therapeutic modalities.PRESENTATION OF CASE: We report a case of a spontaneously ruptured dissecting aneurysm of the middle colic artery, which was managed with an emergency laparotomy and aneurysmatectomy. Interestingly, no evidence of vasculitis, infection or collagen disease was discovered during the histopathology examination of the specimen.DISCUSSION: The treatment of idiopathic spontaneous intra-abdominal haemorrhage revolves around patient resuscitation and management of the source of bleeding. In case of a ruptured aneurysm of the middle colic artery, the surgical management includes emergency laparotomy, arterial ligation and resection of the aneurysm. Transarterial embolisation has been suggested as a safe and less invasive alternative approach.CONCLUSION: A ruptured middle colic artery aneurysm should be included in the differential diagnosis of any unexplained intra-abdominal haemorrhage. Aneurysmatectomy is the treatment of choice, with radiologic interventional techniques gaining ground in the management of this entity.