In a population of dually diagnosed patients receiving assertive community treatment we used the theoretical framework of the transtheoretical model to establish (a) the proportions and characteristics of patients who were not motivated for treatment for psychiatric symptoms and substance use, (b) the proportion of patients who moved towards behavioral change after about 1 year, and examine how this change was related with clinical outcome; and (c) the sequence of change processes. Chi square tests and T tests were used to compare the patient characteristics and outcomes of patients who remained in precontemplation with those who progressed. During follow-up, 47 % of the patients came out of the precontemplation phase for treatment of psychiatric symptoms and 38 % for substance use behavior. Those who remained in precontemplation benefited less from treatment. Of those who did move forward, most appeared to become motivated for psychiatric treatment before becoming motivated to reduce substance use.