**Abstract**

Anticoagulation during extracorporeal membrane oxygenation (ECMO) is necessary to prevent catastrophic circuit clotting, but significant morbidity and mortality continue to be attributed to hemorrhagic and thrombotic complications. Due to the inflammatory response from the extracorporeal circuit and developmental hemostasis, anticoagulation can be challenging particularly for pediatric patients. Unfractionated heparin (UFH) is the gold standard anticoagulant used in ECMO, but there is an expanding area of research evaluating other anticoagulants, such as direct thrombin inhibitors. This chapter provides an overview of anticoagulant options for pediatric patients on ECMO as well as describes the various tests used to monitor and titrate anticoagulation.

**Keywords:** extracorporeal membrane oxygenation, anticoagulation, unfractionated heparin, bivalirudin
