Background <p>A pilot program launched in November 2024 to establish and operationalize Antimicrobial Stewardship Programs (ASPs) in Korean hospitals is expected to accelerate nationwide adoption. However, consensus on indicators for evaluating ASP performance remains lacking. This study aimed to develop indicators for evaluating the short- and long-term effectiveness of ASPs.</p> Methods <p>An expert panel comprised 18 specialists from academic societies and government agencies involved in infectious diseases and antimicrobial control in South Korea. Candidate indicators for evaluating ASP effectiveness were identified by five infectious disease specialists through a systematic literature review. The Delphi survey consisted of an initial open-ended round, followed by two multiple-choice rounds (rounds 2 and 3) with an intervening online panel meeting. Responses to the multiple-choice questions were rated on a 7-point Likert scale, and indicators with a content validity ratio of ≥ 0.47 were selected.</p> Results <p>The systematic literature review yielded 59 candidate indicators of ASP effectiveness, which were classified into seven primary categories. After the third-round Delphi survey, the final set of indicators included the following. In the Antibiotic Use Indicators category: (1) days of therapy per 1,000 patient-days, (2) defined daily dose per 1,000 patient-days, (3) reduction rate of broad-spectrum antibiotic use, (4) intravenous-to-oral antibiotic conversion rate, (5) reduction rate of unnecessary combination therapy, and 6) change in antibiotic prescription ratio according to the World Health Organization Access, Watch, and Reserve classification. In the Process-Related Indicators category: (1) appropriate rate of preoperative surgical antibiotic prophylaxis, (2) implementation of therapeutic drug monitoring with dosage recommendations, and (3) establishment of institutional antibiotic use guidelines. In the Department-Specific Indicators related to operating rooms and surgery: (1) appropriate rate of preoperative surgical antibiotic prophylaxis, (2) appropriateness of postoperative antibiotic discontinuation timing, and (3) appropriateness of prophylactic antibiotic selection. Finally, among the Other Indicators, the implementation rate of core ASP elements was selected as an indicator for evaluating ASP effectiveness.</p> Conclusions <p>This study established consensus-based indicators and proposed short- and long-term targets for evaluating the effectiveness of ASPs in Korea. These indicators enable standardized assessment and help inform evidence-based policies for the sustainable operation of ASPs.</p>