The Councils of The American Association for Thoracic Surgery, The Society of Thoracic Surgeons, and The European Association for Cardio-Thoracic Surgery have directed an Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity to review current clinical practice to update and clarify these reporting guidelines. The guidelines are intended to cover treatment of all four cardiac valves in both adult and pediatric patients. Further, these guidelines apply uniformly, irrespective of whether the therapy was carried out as a conventional open operation, as a minimally invasive (video-assisted or robotic) surgical procedure, or with percutaneous interventional catheter techniques.