Abstract: Objective To provide the evidence for the prevention and treatment of hypoxemia after off pump coronary artery bypass grafting (OPCAB) by studying its risk factors. Methods The clinical data about 208 patients who underwent OPCAB in our hospital from March 2004 to August 2012 were retrospectively analyzed. The patients were divided into non-hypoxemia group and hypoxemia group according to the occurrence of hypoxemia after OPCAB. The risk factors for hypoxemia after OPCAB were studied by univariate and multivariate analysis. Results Of the 208 patients, 61 (29.3%) developed hypoxemia after OPCAB. Univariate analysis revealed that age, BMI, smoking, NYHA class Ⅲ-Ⅳ, triple-vessel disease, EF＜ 30%, cardiogenic shock, and emergent procedure were signifcantly different between non-hypoxemia group and hypoxemia group (P＜ 0.05). Multivariate logistic regression analysis showed that age, BMI, smoking, NYHA class Ⅲ-Ⅳ, triple-vessel disease, EF＜ 30%, and emergent procedure were the independent risk factors for hypoxemia after OPCAB. Conclusion Hypoxemia after OPCAB is related with age, BMI, smoking, NYHA class Ⅲ-Ⅳ, triple-vessel disease, EF＜ 30%, and emergent procedure.