As a participant in the American Board of Internal Medicine Foundation’s Choosing Wisely^® campaign, ASCO has issued a “Top Five” list of common, costly procedures in oncology that are not supported by evidence and that should be questioned. ASCO’s Cost of Cancer Care Task Force, developed the list through a comprehensive review of published studies and current guidelines from ASCO and other organizations. The final list also reflects input from more than 200 oncologists, including the society’s Clinical Practice Committee, the leadership of the state/regional oncology societies, as well as other leading oncologists and patient advocates. In addition to the Top Five list, a full manuscript further detailing the background, methods, and results of ASCO’s efforts is published in the Journal of Clinical Oncology.