BACKGROUND: Apnoeic oxygenation using high-flow nasal oxygen is becoming a commonly used technique in adult patients undergoing laryngotracheal surgery. Despite widespread adoption, there are no best practice guidelines governing its safe delivery. OBJECTIVE: To develop a checklist for use during laryngotracheal surgery to guide the safe delivery of apnoeic oxygenation using high-flow nasal oxygen. DESIGN: Recognised experts in the field of apnoeic oxygenation were invited to participate in a Delphi process to establish essential items for inclusion in the safety checklist. An online Delphi survey platform was used to facilitate this process. SETTING: A panel of 36 experts was assembled from 11 countries. They participated voluntarily in an 8-week Delphi process that included one preliminary round, two electronic voting rounds and a final virtual roundtable discussion. A small steering group was responsible for leading the Delphi process, collating the electronic voting responses, analysing the results and compiling the final checklist. MAIN OUTCOME MEASURES: The consensus threshold for inclusion/exclusion of items in the safety checklist was set at at least 80% for the first and second electronic voting rounds. The consensus threshold was set at 70% for the final roundtable discussion. RESULTS: The final checklist comprises 19 items, sub-divided into pre-procedure, peri-procedure and post-procedure aspects of patient care. The Delphi process was well attended, with an expert attrition rate of only 6%. A number of items reached more than 90% consensus, including the requirement to establish patients' suitability for the technique in advance of surgery and preparedness for the immediate implementation of an agreed individualised rescue oxygenation strategy. CONCLUSION: A Delphi process involving international experts has formulated a 19-item checklist for guiding the safe delivery of apnoeic oxygenation using high-flow nasal oxygen in adult patients undergoing laryngotracheal surgery. Further studies are required to assess the effects of this checklist on patient safety and outcomes.