Background: Delirium in the post-anesthesia care unit (PACU) may be associated with worse outcomes in children with moyamoya disease (MMD). This retrospective study aimed to describe the prevalence of PACU delirium in children with MMD and investigate its risk factors.Methods: Patients with MMD aged < 15 years who underwent indirect revascularization between January 2014 and October 2023 were included in this study. Delirium was assessed using the Pediatric Anesthesia Emergence Delirium Scale. Potential risk factors for PACU delirium were evaluated using multivariate logistic regression.Results: PACU delirium occurred in 245 (33%) of the 750 hemispheric procedures performed in 522 patients. Delirium was associated with a higher incidence in patients undergoing the first revascularization (37%) than in those undergoing the second (25%; P = 0.002). Cerebral infarction as the initial presentation (odds ratio [OR]: 4.64, first revascularization), high pediatric moyamoya magnetic resonance imaging (MRI) score (OR: 2.75, first revascularization; OR: 3.50, second revascularization), and high intraoperative mean arterial pressure variability (mmHg/min) (OR: 9.17, first revascularization; OR: 8.82, second revascularization) were associated with PACU delirium. Conversely, total intravenous anesthesia (TIVA) was associated with a lower incidence of PACU delirium (OR: 0.46, first revascularization; OR: 0.25, second revascularization).Conclusions: A significant proportion of patients with MMD developed delirium in the PACU. High intraoperative blood pressure variability and preoperative MRI lesions are independent risk factors for PACU delirium in children with MMD. TIVA may exert a protective effect against PACU delirium. Further studies are required to clarify the causality of these associations.