Overuse and misuse of antibiotics have contributed to the growing problem of antimicrobial resistance and serious side effects including Clostridium difficile infection. The Centers for Disease Control and Prevention estimates that more than 2 million people are infected by multidrug-resistant organisms every year. They propose that promoting antimicrobial stewardship programs (ASP) is an essential component to combat this growing threat. One of the major barriers in implementing effective ASP is the availability of reliable measures which reflect intervention effectiveness. Measuring ASP can be divided into four categories: antimicrobial consumption, process measures, outcome measures, and financial. This article reviews the strengths and weaknesses of the current measures.