Abstract Background Postoperative delirium is common in the elderly and is associated with a significant increase in mortality, complications, length of hospital stay and admission in long care facility. Although several interventions have proved their effectiveness to prevent it, the Cochrane advises an assessment of multifaceted intervention using rigorous methodology based on randomized study design. Our purpose is to present the methodology and expected results of the CONFUCIUS trial, which aims to measure the impact of a multifaceted program on the prevention of postoperative delirium in elderly. Method/Design Study design is a stepped wedge cluster randomized trial within 3 surgical wards of three French university hospitals. All patients aged 75 and older, and admitted for scheduled surgery will be included. The multifaceted program will be conducted by mobile geriatric team, including geriatric preoperative consultation, training of the surgical staff and implementation of the Hospital Elder Life Program , and morbidity and mortality conference related to delirium cases. The primary outcome is based on postoperative delirium rate within 7 days after surgery. This program is planned to be implemented along four successive time periods within all the surgical wards. Each one will be affected successively to the control arm and to the intervention arm of the trial and the order of program introduction within each surgical ward will be randomly assigned. Based on a 20% reduction of postoperative delirium rate (ICC = 0.25, α = 0.05, β = 0.1), three hundred sixty patients will be included i.e. thirty patients per service and per time period. Endpoints comparison between intervention and control arms of the trial will be performed by considering the cluster and time effects. Discussion Better prevention of delirium is expected from the multifaceted program, including a decrease of postoperative delirium, and its consequences (mortality, morbidity, postoperative complications and length of hospital stay) among elderly patients. This study should allow better diagnosis of delirium and strengthen the collaboration between surgical and mobile geriatric teams. Should the program have a substantial impact on the prevention of postoperative delirium in elderly, it could be extended to other facilities. Trial registration ClinicalTrials.gov: NCT01316965