Background Minimally invasive cardiac surgery and closed chest cardiopulmonary bypass (CPB) techniques continue to evolve.Previous reports have demonstrated the benefits of fluoroscopy guided cannulation for endovascular CPB during port access cardiac surgery.However,few data are available on the role of transesophageal echocardiography (TEE) guided cannulation for peripheral CPB during robotic cardiac surgery.The purpose of this study was to evaluate TEE guided cannulation for peripheral CPB during robotic cardiac surgery.Methods We performed a retrospective analysis of intraoperative data of 129 consecutive patients underwent robotic cardiac surgical procedures requiring peripheral CPB from September 2007 to August 2011,which was established using femoral arterial inflow and kinetic venous drainage by way of the femoral vein and right intal jugular vein and a transthoracic aortic cross clamp.TEE was used to guide cannulation of the inferior vena cava (IVC),superior vena cava (SVC),and ascending aorta (AAO).The success rate and the complication rate of TEE guided cannulation for peripheral CPB were evaluated and compared with the results of fluoroscopy guided cannulation in a historical control group.Results One hundred and twenty-nine consecutive patients underwent robotic cardiac surgical procedures requiring peripheral CPB.There were 67 female (51.9％) and 62 male (48.1％) patients,ranging in age from 13 to 70 years (mean (43.94 ± 13.82) years) and body surface area 1.32 to 2.39 m2 (mean (1.71 ± 0.20) m2).Some 61 (47.3％) patients underwent mitral valve repair,27 (20.9％) mitral valve replacement,27 (20.9％) left atrial myxoma removal,and 14(10.9％) ventricular septal defect repair.Of the 129 patients,TEE guided cannulation of the IVC or SVC was successful in all patients (100％),and no puncture related complications occurred in all patients.Of the 129 patients,successful cannulation of the AAO was achieved in all patients (100％),and aortic perforation occurred in 1 patient (0.78％) under TEE guidance.Of the 42 patients in the historical control group,successful cannulation occured in 39 patients (92.86％),and major complications occurred in 3 patients (7.14％) under fluoroscopy guidance.TEE guided cannulation of the AAO significantly improved success rate (100％ vs.92.86％,P=0.014) and decreased complication rate (0.78％ vs.7.14％,P=0.046).Conclusion TEE may be useful in guiding successful placement of the cannulae in the IVC,SVC,and AAO in the establishment of peripheral CPB during robotic cardiac surgery.