Background: Deep sedation in critically ill children undergoing extracorporeal membrane oxygenation (ECMO) can be challenging. Volatile anesthetics like sevoflurane can be a good alternative for patients hospitalized in pediatric intensive care units, in whom adequate sedation is difficult to obtain. Case description: We report here the first pediatric case of a patient under extracorporeal membrane oxygenation receiving sedation by sevoflurane using the AnaConDa-S device. This 2-year-old girl, suffering from congenital diaphragmatic hernia, was put on extracorporeal membrane oxygenation due to a persistent pulmonary hypertension following metapneumovirus infection. Despite high doses of drugs, neither satisfactory sedation nor analgesia could be reached. Sevoflurane allowed her to be released and we were able to wean her from certain drugs. Her physiological parameters and the indicators of pain and sedation improved. Conclusion: Anesthesia using sevoflurane with the AnaConDa-S device is efficient for children under ECMO. Clinical significance: This is the first pediatric report on anesthesia with sevoflurane under ECMO.