BACKGROUND Airway assessment and management are cornerstones of anaesthesia, yet airway complications remain an important source of morbidity. OBJECTIVE We performed a before-and-after evaluation of a collaborative intervention to improve adherence to airway assessment and management guidelines in patients scheduled for surgery under general anaesthesia. DESIGN A prospective, multicentre before-and-after evaluation of a collaborative intervention. SETTING Collaborative intervention to improve adherence to airway assessment and management guidelines in patients scheduled for surgery under general anaesthesia. Data were collected on 21 consecutive days before and after the intervention. PARTICIPANTS Anaesthetists with staff or residency positions at 22 hospitals. Patients aged 18 years or older undergoing nonemergency surgery were recruited. INTERVENTION Establishing a learning network that included local leaders, meetings to share experiences and knowledge, interactive sessions and provision of printed materials on airway assessment and management. Clinical airway management for general anaesthesia was provided by the anaesthetists participating in the study. MAIN OUTCOME MEASURES Outcomes were the completion of airway assessment at the preanaesthetic visit, rates of unanticipated difficult airway, algorithm adherence and related airway complications. RESULTS The study included 3753 patients (1947 preintervention and 1806 postintervention). The percentage of patients with a complete airway assessment increased from 25.1% preintervention to 48.4% postintervention (P<0.001). The incidences of unanticipated difficult airway were 4.1% before the intervention and 3% after it (P0.433). Rates of adherence to the algorithms for anticipated and unanticipated difficult airway management were similar in the two periods. The incidences of related adverse events were also similar. CONCLUSION The collaborative intervention was effective in improving airway assessment but not in changing difficult airway management practices.