An 11-month-old girl with an oesophageal foreign body was presented: from the radiographic appearance it was presumed to be a coin. Microlaryngoscopy 5 h after ingestion revealed a button battery impacted in the hypopharynx with severe damage to the oesophageal mucosa. The patient was intubated for 6 days in the intensive care unit because of stridor and respiratory distress. Repeat microlaryngoscopy demonstrated bilateral vocal cord palsy, which was presumed to be secondary to the involvement of the recurrent laryngeal nerves in the injury. We recommend that in the absence of a history of observed ingestion, it should be assumed that coin-like foreign bodies are button batteries until proven otherwise.