The American Association for Thoracic Surgery (AATS) is an international association of cardiothoracic surgeons. It was founded in 1917 by the earliest pioneers in the field of thoracic surgery. Headquartered in Beverly, Massachusetts, it has over 1,200 members from 35 countries. To be considered for membership, a surgeon must have a proven record of distinction within the field and have made meritorious contributions to the knowledge of cardiothoracic disease and its surgical treatment.