OBJECTIVES: Prescription drug monitoring programs (PDMPs) are viewed as a tool to reduce abuse and diversion of prescription controlled substances (CS), although little is known about their effectiveness in achieving these goals. The purpose of this project was to assess the impact of the Kentucky All Schedule Prescription Electronic Reporting program (KASPER) on pharmacists’ dispensing behavior and to evaluate its perceived effectiveness in reducing drug abuse, diversion, and doctor shopping. METHODS: Surveys were mailed to 2,018 pharmacists in Kentucky. After two weeks, a reminder postcard and second survey were sent to non-responders. Responses were coded and descriptive analysis was conducted in STATA 11. RESULTS: Responses were received from 575 pharmacists (response rate = 28.5%). The majority (77%) indicated they had requested a patient’s CS history through KASPER. For those who had not utilized KASPER, the primary reason was lack of Internet access at the practice-site. When asked if their CS dispensing has changed since KASPER implementation, 67% indicated no change while 13% indicated a decrease in dispensing and 15% indicated an increase. For those reporting a decrease, reasons cited include implementation of KASPER (36%), increased law enforcement activity (15%) and media coverage of drug abuse and diversion (8%). The majority (83%) of respondents believe that KASPER is an effective tool to reduce drug abuse and diversion and 79% feel it is an effective tool to reduce doctor shopping. CONCLUSIONS: Internet access was the primary reason for not using KASPER. Most pharmacists have not perceived a change in CS dispensing since KASPER implementation. Those who do perceive a change are nearly equally divided between an increase and decrease in dispensing. Overall, the majority of respondents believe that KASPER is an effective tool to reduce drug abuse, diversion, and doctor shopping. Further research is necessary to assess the full effectiveness of PDMPs.