A patient had massive hematemesis due to a fistula between an unsuspected aberrant right subclavian artery and the esophagus, with the fistula caused by prolonged esophageal intubation. Lack of awareness of this complication delayed the correct diagnosis, which was eventually made at a second angiographic study. With knowledge of the fistula, this potentially fatal situation can be promptly diagnosed by endoscopy and emergency angiography. Transcatheter embolization is suggested as a potential alternative to surgery in the treatment of the aberrant right subclavian artery--esophageal fistula.