Intraoperative surgical prosthetic heart valve (SHV) choice is a key determinant of successful surgery and positive postoperative outcomes. Currently, many controversies exist around the sizing and labeling of SHVs rendering the comparison of different valves difficult. To explore solutions, an expertValve Labelling Task Force was jointly initiated by the European Association for Cardio-Thoracic Surgery (EACTS), The Society of Thoracic Surgeons (STS) and the American Association for Thoracic Surgery (AATS). The EACTS-STS-AATS Valve Labelling Task Force, comprising cardiac surgeons, cardiologists, engineers, regulators and representatives from the International Organization for Standardization (ISO), and major valve manufacturers, held its first in-person meeting in February 2018 in Paris, France. This article was derived from the meeting's discussions. The Task Force identified the following areas for improvement and clarification: reporting of physical dimensions and characteristics of SHVs determining and labeling of SHV size, in vivo and in vitro testing, and reporting of SHV hemodynamic performance and thrombogenicity. Furthermore, a thorough understanding of the regulatory background and the role of the applicable ISO standards, together with close cooperation between all stakeholders (including regulatory and standard-setting bodies), is necessary to improve the current situation. Cardiac surgeons should be provided with appropriate information to allow for optimal SHV choice. This first article from the EACTS-STS-AATS Valve Labelling Task Force summarizes the background of SHV sizing and labeling and identifies the most important elements where further standardization is necessary.