The diversion of legitimate controlled substances to the black market is a major cause of medical emergencies, fatalities, and drug-related dependencies. The effects harm not only the illegal user, but also the legitimate patient who may be getting shorted on treatments and innocent medical providers who may be charged with false claim offenses or other professional failures because of diversions that take place during their watch. The dollar magnitude of this crime is estimated to rival the black markets for both crack cocaine and heroine combined. This article addresses the various ways prescription drugs are diverted to the black market, some monitoring programs employed by the states, and guidelines that doctors, pharmacists, and other providers can use to protect themselves against possible liabilities arising from the diversion of prescription drugs. We will also address some of the oppositions to monitoring programs that have been asserted and replies to these oppositions.