Core elements of effective antibiotic stewardship programs (ASPs) have been identified and evidence-based guidelines have been developed for implementation. The majority of the evidence used for these guidelines are from published studies on the effectiveness of ASPs in large academic or large community hospitals. A significant portion of healthcare in the United States, however, takes place in small hospitals. In 2015, 73% of US hospitals had < 200 beds (4,057 hospitals) and accounted for 29% of all US inpatient bed days. Limited studies on the effectiveness of antibiotic stewardship implementation have been performed in hospitals with < 200 beds. Antibiotic use rates and selection patterns in these small hospitals are similar to that of large hospitals and the majority of small hospitals lack formal ASP that meet the CDC's core elements. The objective of this real-world implementation study was to assess the effectiveness of three ASP strategies of escalating intensity designed specifically for small hospitals within a vertically integrated healthcare delivery system.