Studies focusing on the readiness of persons to change have burgeoned in recent years. Assessing readiness for change is viewed as important for interventions aimed at promoting health behaviors, such as smoking cessation and substance abuse programs. This study is the first to examine readiness for change, as conceived by Prochaska and his colleagues, among a sample of persons with severe mental illness who were about to participate in a vocational rehabilitation program. We examined the reliability, validity, and other psychometric properties of the Change Assessment Scale and its ability to predict attrition and actual change.