We report the first case of robot-assisted thoracoscopic resection of a mediastinal parathyroid adenoma in the aorto-pulmonary window. Intervention planning was based on preoperative CT-MIBI image fusion, a new imaging modality that enabled reliable and precise localization of the parathyroid. The technique consists of taking MIBI-SPECT and CT separately, using a fixation unit that provides reproducible positioning of the patients head and neck. The data sets are then superimposed upon each other using special software. After the localization process, a minimally invasive operation was performed using the DaVinci operating robot. The procedure proved not only to be feasible but also safe and not time-consuming. The postoperative course was uneventful, and the patient was discharged 4 days postoperatively. Compared to conventional thoracoscopic surgery, the robotic operating system provides better visualization of the operating field and facilitates the movement of the instruments. Precise preoperative imaging enables the careful planning of robot-assisted surgery for ectopic parathyroids located at relatively inaccessible regions such as the anterior mediastinum.