We present a case of fatal aortoesophageal fistula in a 14 month old girl. She presented to the emergency department with acute hematemesis. A foreign body in the esophagus was identified on chest X-ray. Despite intensive resuscitation, she went into cardiac arrest and died. In the three weeks prior to death, she had non-specific symptoms; based on an elevated urinary polymorph level and Escherichia coli culture, she was diagnosed with a urinary tract infection and prescribed antibiotics. Postmortem imaging revealed a metallic foreign body in the esophagus consistent with a button battery and autopsy revealed an aortoesophageal fistula caused by a 20 mm imprint code CR 2025 button battery. It is unclear how long the battery had been in situ. We highlight the importance of a high index of suspicion for battery ingestion in children, the need for clinicians to recognize a button battery on radiography, and the value of routine postmortem imaging in the detection of findings that may be relevant to the autopsy. Although rare, fatal cases due to button battery ingestion are preventable.