Court-mandated treatment, which requires offenders convicted of alcohol or other drug-related crimes to participate in treatment for their substance abuse problems or face legal consequences, has long been a component of sanctioning for driving under the influence (DUI) and is a primary path of entry into alcoholism treatment for many people with problem drinking. Several issues are relevant to mandated treatment: screening, assessment and referral, effectiveness, DUI events as opportunities for intervention, brief interventions for offenders outside of mandated treatment, and cost-effectiveness of mandated treatment. Treatment effectiveness depends to some extent on offenders' motivation to participate, and offenders may resist treatment when their participation is coerced. Types of treatment such as motivational enhancement therapy may prove cost-effective with these involuntary participants. More research is needed into the changing DUI population, impaired driving and multidrug use, and new technologies for monitoring DUI offenders.