Prescription drugs represent the second most abused class of drugs in the United States. Despite this, and despite the rapid growth of prescription drug abuse, the problem has largely been ignored in the substance-use research community. The medical community requires a better understanding of what contributes to the misuse of prescription drugs. We propose several analyses that will better inform us on the important characteristics of prescription drug abusers and some of the causes of prescription drug abuse. First, based on data from the National Survey on Drug Use and Health, we will produce a profile of who uses prescription drugs for non-medical purposes. We will create separate profiles according to age (12-17, 18-25, and 26+). Among the characteristics we will examine are: employment status, job characteristics, health, health coverage, and prior and current illicit drug use. We will examine how these profiles of users have changed over time and how they vary by race/ethnicity and gender. The second part of the proposed analysis is to determine whether prescription drug abuse is dependent on the prices of illicit drugs. This should inform us on whether prescription drugs are used as a complement to illicit drugs or perhaps a substitute when illicit drugs are too expensive or otherwise not available. We will determine whether the use of prescription drug for non-medical purposes is more responsive to the prices of other illicit drugs than are illicit drugs.