This document updates the 2014 Core Elements for Hospital Antibiotic Stewardship Programs and incorporates new evidence and lessons learned from experience with the Core Elements. The Core Elements are applicable in all hospitals, regardless of size. There are suggestions specific to small and critical access hospitals in Implementation of Antibiotic Stewardship Core Elements at Small and Critical Access Hospitals (12).There is no single template for a program to optimize antibiotic prescribing in hospitals. Implementation of antibiotic stewardship programs requires flexibility due to the complexity of medical decision-making surrounding antibiotic use and the variability in the size and types of care among U.S. hospitals. In some sections, CDC has identified priorities for implementation, based on the experiences of successful stewardship programs and published data. The Core Elements are intended to be an adaptable framework that hospitals can use to guide efforts to improve antibiotic prescribing. The assessment tool that accompanies this document can help hospitals identify gaps to address.