In February 2023, the American Board of Emergency Medicine (ABEM) approved modifications to the Advanced Emergency Medicine Ultrasonography (AEMUS) Core Content, which defines the areas of knowledge considered essential for the practice of AEMUS. This manuscript serves as a revision of the AEMUS Core Content originally published in 2014. The revision of the Core Content for AEMUS training aims to establish standardized education and qualifications necessary for AEMUS fellowship program leadership, clinical application, administration, quality improvement, and research. The Core Content provides the organizational framework and serves as the basis for the development of content for the Focused Practice Examination (FPE) administered by ABEM. AEMUS fellowship directors may reference the Core Content when designing AEMUS fellowship curricula to help prepare graduates for the autonomous practice of AEMUS and the FPE. In this article, an updated revision of the previously published AEMUS Core Content is detailed, and the entire development of the Core Content is presented.