Extensive evidence from the laboratory and the clinic suggests that drug addiction can be viewed as operant behavior and effectively treated through the application of principles of operant conditioning. Contingency management interventions that arrange for the direct reinforcement of drug abstinence or of other therapeutically important target behaviors (e.g., regular use of drug abuse treatment medications) are among the most studied type of operant treatments. Behavior analysts have contributed to the substantial and rapidly growing literature on operant treatments for drug addiction, but the publications of this work usually appear in medical, clinical psychology, or drug abuse journals. This special issue of the Journal of Applied Behavior Analysis represents an effort to bring this important work to the attention of the behavior-analytic community. The articles in this special issue illustrate both the enormous potential of contingency management interventions to address the serious and seemingly intractable problem of drug addiction as well as the real challenges involved in attempting to develop and disseminate treatments that will produce substantial and lasting changes in the lives of individuals plagued by the chronic problem of drug addiction.