Introduction: Button battery ingestion in children can be fatal if oesophageal perforation occurs. Such children require chest radiography in the emergency department to determine the button battery position and number. Current guidelines recommend that a button battery impacted in the oesophagus should be removed within two hours. We developed a clinical tool (the button battery impaction score) to estimate the risk of oesophageal impaction and help determine the most appropriate healthcare facility for initial assessment, either a local medical centre or a medical centre with the infrastructure for endoscopic retrieval. Methods: A multicentre retrospective study was conducted over seven years in eight French poison centres. We included patients aged less than 12 years with radiography showing the button battery position and a symptom description before radiography. Button battery impaction scores were calculated using backward stepwise selection. Results and discussion: A total of 1,430 patients were included, of whom 86, 461, and 375 had a button battery in their oesophagus, stomach, and post-pyloric position, respectively. No button batteries were identified by radiography in 508 patients. Sixteen of thirty-five factors independently predicted oesophageal impaction before chest radiography (P < 0.05). After the backward stepwise selection, the following seven factors contributed to the button battery impaction score: cough, drooling, dysphagia/food refusal, fever, pain (unspecified location), vomiting, and button battery >= 15 mm. The button battery impaction score showed an area under the curve value of 0.87, a negative predictive value of 0.98, and a sensitivity of 0.86. No cases of death, stricture, or haemorrhage were observed in patients with negative scores, including those with oesophageal impaction. Conclusions: A button battery impaction score used readily available data to predict the risk of oesophageal impaction after button battery ingestion and before chest radiography. When further validated, this rapid tool may be widely applicable in determining an appropriate facility for patient transfer to either a local medical centre or a medical centre with the infrastructure for endoscopic retrieval.Read less <