This study examined the long-term relationship of changes in the motivation to remedy alcohol abuse to alcohol use severity among patients with a dual diagnosis of substance abuse disorder and severe and persistent mental illness. Linear regression analyses showed that patients who increasingly recognized alcohol use problems over a 9-month period exhibited significantly greater alcohol use severity at 9 months and a significant increase in alcohol use severity over time. Moreover, patients who became increasingly determined to take actions against alcohol use over a 9-month period exhibited significantly lower alcohol use severity at 9 months and a significant decrease in alcohol use severity over time. The findings support Prochaska et al.'s transtheoretical model of the motivation for change. They suggest that the recognition of alcohol use problems comes along with learning adverse consequences of alcohol use and that increased determination to take actions is critical to the long-term behavioral changes in alcohol use.