BACKGROUND: Postoperative delirium (POD) is a severe complication associated with various adverse outcomes, especially in older patients. Although the incidence and risk factors for POD have been explored in general surgery, they have not been fully elucidated. Early identification of high-risk patients and active preoperative intervention are considered essential for the prevention of POD. Recently, psychiatric consultation intervention have been shown to prevent delirium. This study investigated the effect of preoperative psychiatric interventions on preventing POD in our specific surgical context. MATERIALS AND METHODS: This retrospective, single-center observational study included 86 patients who underwent major oral and maxillofacial surgery with free flap reconstruction between 2016 and 2023. The effect of psychiatric intervention were compared between patients with and without delirium. RESULTS: Preoperative psychiatric intervention did not reduce the incidence of POD. The incidence of POD was 29.1 %. Univariate analyses showed no significant associations between POD and any clinical variables. CONCLUSION: There was no difference in the incidence of POD between patients who received preoperative psychiatric intervention and those who did not, and further investigation is needed to determine the efficacy of preoperative psychiatric intervention in the prevention of POD.