Extracorporeal membrane oxygenation (ECMO) is increasingly being employed in South African intensive care units for the management of patients with refractory hypoxaemia and for haemodynamic support, particularly following cardiothoracic procedures. ECMO is expensive, however, and there is a danger that this rescue modality may be abused or utilised unnecessarily or in situations where further intensive therapy is futile. This brief review provides an overview of the techniques available, and the recommended indications and exclusions for venovenous ECMO in particular.