The primary purpose of this study was to examine the effectiveness of mapping-enhanced counseling with less educated methadone clients (i.e., clients with no high school diploma or GED). Results indicated that less educated clients exposed to node-link maps during treatment showed better 12-month follow-up outcomes than similar clients exposed to standard methods of counseling. Less educated mapping clients were less likely than their standard counterparts to have used drugs and to have engaged in criminal activities in the 6 months before the follow-up interview.