Background Cross-sectional studies suggest that patients treated with extracorporeal membrane oxygenation (ECMO) have adverse health outcomes and high risk for mental health problems after discharge. Objectives To describe the recovery of discharged patients during the first year after ECMO. Methods In a prospective cohort study, data were collected 3, 6, and 12 months after discontinuation of ECMO and discharge. Postal surveys included the 36-Item Short Form Health Survey, the EuroQol-5-Dimensions-5-Levels health questionnaire, the Hospital Anxiety and Depression Scale, and the Impact of Event Scale-Revised. Telephone interviews were used to track adverse physical outcomes. The Telephone Interview for Cognitive Status questionnaire was administered at the end of each call. Results Patients in the study experienced more physical than mental adverse health outcomes, and the risk for mental problems was 2 or 3 times the rate expected. Adverse physical outcomes were common. One-quarter of patients remained significantly restricted; some had severe neurological impairments of the lower extremities. On cognitive tests, about half scored inconclusive or mildly impaired. Patients were often admitted to the hospital. Conclusions Physical health was more severely impaired than was mental health, and both types improved over time. The EuroQol-5-Dimensions-5-Levels instrument was useful for detecting neurological problems of the lower extremities early and may qualify as a core outcome measure for patients treated with ECMO.