This article describes a four-session intervention designed for persons with co-occurring substance abuse and schizophrenia-spectrum disorders, to be administered as an add-on module to supplement ongoing mental health treatment in an outpatient setting. The intervention targets those dually diagnosed individuals with low readiness-to-change as indicated by current use, and/or low level of engagement in treatment for substance abuse. The intervention is designed to increase problem recognition, to enhance motivation to change maladaptive patterns of substance use, and to facilitate engagement in substance abuse treatment. To achieve these goals, the authors have adopted constructs from the Transtheoretical Model of Change, the authors used principles of motivational and harm reduction interventions, and tailored them to the target population.