PDMPs are used by State and local governments to control prescription drug abuse and diversion. In most States, participation in the PDMP by prescribers and dispensers is voluntary. Several States, however, have passed a statutory mandate requiring enrollment and use of a PDMP by prescribers and dispensers. As of July 2013, 13 States had adopted legislation mandating registration of prescribers, and in some cases dispensers, while 16 States had legislation mandating that prescribers and in some cases dispensers use the PDMP in certain circumstances. These States are, respectively, Alabama, Arizona, Connecticut, Delaware, Kentucky, Maine, Massachusetts, Mississippi, New Hampshire, New Mexico, Tennessee, Utah, and Vermont; and Colorado, Delaware, Kentucky, Louisiana, Massachusetts, Minnesota, Nevada, New Mexico, New York, North Carolina, Ohio, Oklahoma, Rhode Island, Tennessee, Vermont, and West Virginia. This briefing highlights the experiences of three of these States in mandating the use of PDMPs. These States are Kentucky, Tennessee, and New York. Review of these efforts indicated that the statutory mandates increased enrollment in PDMPs and that this increase was associated with declines in opioid prescribing and doctor shopping. It is suggested that States consider implementing these mandates according to the limitations of their resources and in a manner that will eventually lead to full participation by prescribers and dispensers.