Objective: To explore the risk factors for postoperative acute respiratory distress syndrome (ARDS) in Stanford type A acute aortic dissection (AAD) patients. Methods: This study included 64 patients with Stanford type A AAD who underwent Sun's procedure. The patients were divided into an ARDS group (PaO2/FiO(2) < 200 mmHg) and a non-ARDS group (PaO2/FiO(2) = 200 mmHg). We compared the patients' perioperative clinical features in the two groups. A multivariate binary logistic regression was used to analyze the risk factors for ARDS in the Stanford type A AAD patients. Results: The incidence of postoperative ARDS was 56.25%. There were 13 deaths in the 6-month follow-up, including 8 in the ARDS group and 5 in the non-ARDS group. There were differences in the body mass index (BMI) levels, the times from onset to operation, the preoperative white blood cell counts, the preoperative hemoglobin levels, the preoperative alanine aminotransferase levels, the preoperative blood creatinine levels, the preoperative PaO2/FiO(2), intraoperative blood transfusion volumes, the assisted mechanical ventilation times, and the durations of the intensive care unit stays between the two groups (all P < 0.05). The logistic regression analysis revealed that a BMI >= 25 kg/m(2), a time from onset to operation >= 24 hours, a preoperative white blood cell count >= 10x109/L, and a preoperative PaO2/FiO(2) < 300 mmHg were the independent risk factors for postoperative ARDS in patients with Stanford type A AAD. Conclusions: ARDS occurs often in Stanford type A AAD patients. A BMI >= 25 kg/m(2), a time from onset to operation >= 24 hours, a preoperative white blood cell count >= 10x10(9)/L, and a preoperative PaO2/FiO(2) < 300 mmHg are the independent risk factors for postoperative ARDS in these patients.