Prescription drug monitoring programs are designed to facilitate the collection, analysis, and reporting of information on the prescribing, dispensing, and use of prescription drugs within a state. An overriding goal of PDMPs is to uphold both the state laws ensuring access to appropriate pharmaceutical care by citizens and the state laws deterring diversion. While in recent years PDMPs have gained notoriety and have been recognized as important programs, it was not always that way. The history of PDMPs spans almost a century and is riddled with opposition, misperception, and misinformation regarding their purpose and value.