Acute phlegmonous esophagitis is an unusual bacterial infection characterized by suppurative inflammation of the esophageal wall that can affect submucosa and muscular layer with sparing of the mucosa. Since the pathogenesis and clinical features of acute phlegmonous esophagitis have remained unclear due to the rarity of the disease. It has a high mortality rate because the diagnosis is usually made delayed. A 60-year-old woman visited our hospital due to sore throat and odynophagia with no underlying disease. Computer tomography revealed a retopharyngeal abscess with acute phlegmonous esophagitis. She became febrile and dyspnea was getting worse due to airway obstruction of the retropharyngeal abscess. The patient was treated emergent surgical drainage of the retropharyngeal abscess and intense antibiotic therapy. Phlegmonous esophagitis was subsided sequentially without further surgical procedure such as a esophagectomy. The authors experienced a case of acute phlegmonous esophagitis as a complication of the retropharyngeal abscess and report it with review of literature.