Each year, approximately 2 million people in the United States contract an infection during a hospital stay. An increasing percentage of these institutionally acquired infections are attributed to antimicrobial-resistant organisms. At the same time, studies and surveys suggest that as much as half of all antimicrobial use is inappropriate. Recommendations for preventing and reducing antimicrobial resistance in hospitals stress the importance of improving antimicrobial use, referred to as antimicrobial stewardship, at the institutional level. Antimicrobial stewardship programs have served as wake-up calls to both clinicians and health care administrators. We review the more recent literature concerning the impact of antimicrobial stewardship programs on costs, outcomes, and resistance and summarize important considerations for implementation of these programs.