Upper gastrointestinal bleeding (UGIB) in children has multiple etiologies but fortunately is not encountered commonly by pediatricians. Aorto-esophageal fistula (AEF) in children is a rare cause of UGIB and it is mainly secondary to accidental ingestion of foreign bodies, particularly disc batteries, or after cardiothoracic surgery. In this study, we report a case of a 3-year-old child who developed de novo AEF with no prior injury to the esophagus. The child presented with massive UGIB leading to hypovolemic shock, acute kidney injury, and cardiac arrest. The torrential bleed was controlled using a Sengstaken–Blakemore Tube (SBT), which allowed urgent chest CT angiography as well as subsequent thoracotomy and repair of the fistula Unfortunately, the child succumbed to repeated cardiac arrests secondary to the renal injury and severe acidosis. This case highlights the need for the early recognition of massive UGIB in children and the requirement to make appropriately sized SBTs available in all pediatric gastroenterology units.