Extracorporeal membrane oxygenation (ECMO) can support patients with severe cardiorespiratory failure presenting with hypoxia who would otherwise have not survived. Patient selection for ECMO is challenging and relies on the integration of physiological variables with an assessment of reversibility of the underlying condition or suitability for transplantation. In this review, we focus on patients with cardiorespiratory disease who may present with severe hypoxia. We will discuss the indications and contraindications for ECMO; the evidence for ECMO, which is limited to a small number of clinical trials and registry data; the complications of ECMO; expanding technologies and indications; the development of a multidisciplinary ECMO network; and future research. The aim is to increase knowledge of this important area for respiratory physicians.