Abstract: Objective:To summarize the clinical experience of robotic assisted thymoma dissection with the da Vinci S surgical system. Methods:The clinical data of 3 patients with thymoma treated with da Vinci S system between May 2009 and October 2009were reviewed. The patients were under general anesthesia and had a double-lumen endotracheal tube for selective single lung ventilation during surgery. The patient was positioned at a 30-degree angle and tumor location de-cided which side was elevated. Patient cart was positioned on a 30-degree angle from the patient head, non-operating side. In the robotic procedure, the port for the robotic endoscope was positioned in the 6th intercostal space between the middle and anterior axillary line. The two robotic instrument ports were placed in the3rd and 6th intercostal spaces, one handbreadth left and right of the camera trocar, respectively. An auxiliary port was positioned dorsal between the camera and the left instrument trocar. The tumor and thymus were dissected and then the surrounding fatty tissue was removed. Larger vessels (the thymic vein) were clipped, and smaller ones were sealed by electrocautery. The specimen was taken out in an endobag. Results: All three cases of thymoma and thymus were en block dissected and followed perithymic fatty tissue removal. No intraoperative mortality or major complications were experienced; no conversion to median sternotomy and no extra accesses were used. Surgical duration was80-240 min (136 .7 min on average), all patients were extubated at 16-49h (28.7 h on average) after surgery, blood loss was 30-100 ml (mean63.3 ml), thoracic tube drainage after24h was 100 -250 mL (160 mL on average), with no transfusion in the perioperative period. One case using the left side entrance route had transient left diaphragmatic paralysis and recovered before discharge. Pathologically, there were 2 cases of type B1 and 1 case of type B2 according to the WHO standard. Conclusion:Removing the thymoma and dissecting the perithy-mic fatty tissue in the mediastinum with the da Vinci S system was feasible and the early results are satisfactory.