Recognizing this large scope of practice and the varied nature of the evidence base to support the use of CPB, the Evidence Based Workforce of The Society of Thoracic Surgeons (STS) undertook a project to develop a series of practice guidelines that re ect the evidence base for the use of CPB in the current era. This effort included a collaboration with the Society of Cardiovas- cular Anesthesiologists (SCA) and the American Society of ExtraCorporeal Technology (AmSECT) to summarize available evidence in various areas of CPB. A critically important part of CPB is the use of anticoagulation therapy. To date, there are no evidence-based practice guidelines that de ne the optimal management of anti- coagulation during the conduct of CPB. As a result, practice in this area is highly variable and not stan- dardized in accordance with the evidence base to date. Therefore, the STS recognized this de cit and undertook a collaboration with the SCA and AmSECT to address the evidence gap regarding the use of anticoagulation treatment during CPB. This article reviews relevant published information about the use of anticoagulation for the conduct of CPB and provides a synthesis of the available evidence to create a clinical practice guideline. This guideline represents the initial evidence-based approach to the use of anticoagulation in CPB and is the only available comprehensive guideline of its kind. It is the hope of the authors that this guideline will stim- ulate investigators to amplify and elaborate on the evi- dence available on this topic. Search Methods To identify relevant evidence, a systematic review was outlined and literature searches were conducted in PubMed using standardized medical subject heading (MeSH) terms from the National Library of Medicine list of search terms and were inclusive of the dates January 2000 to December 2015. 