Objectives: Due to breathing movements, radiotherapy of primary lung cancer requires sophisticated methods to ensure accuracy of the high-precision treatment applied. The aim of this study was to show the use of extracorporeal membrane oxygenation for ablative radiotherapy while the lung is totally arrested. Methods: A portable extracorporeal membrane oxygenation device was employed on three separate days without mechanical ventilation to apply stereotactic hypofractionated radiotherapy in three fractions (18 Gy x 3 54 Gy total) to a 68 year old male with a primary tumor (T1N0M0) in the right upper lobe (of the remaining lung). Linear accelerator quality controls (matched isocenter-lasers), patient immobilization monitoring (stereotactic infrared system) and image controls (in cinema mode to observe movements) were made during treatment, and a computed tomography comparison was carried out between pre and post treatment for image verification. Results: Total extra-corporeal membrane oxygenation time was 270, 283 and 380 minutes for each session respectively. Total administered nominal dose was 54 Gy and it was not necessary to discontinue the treatment since neither lung nor tumor movement was observed during this time. During the second and third treatment days, atelectasis appeared, involving the rear of the lower lobe and it was necessary to increase FiO2 to 0,5. The only post-procedure complication has been a seroma in the groin which was resolved with local wound care. Conclusion: The described technique of veno-arterial extra-corporeal membrane oxygenation allows the safe arrest of the lung, the immobilization of the tumor and provides enough time for highly accurate ablative radiation therapy.