Few studies have examined nonsmokers who enter treatment for alcohol use disorders to see what happens to their smoking status over time. Such individuals may be vulnerable to initiating tobacco use during or after treatment. Thus, the present study examined changes in the smoking status of the 387 baseline nonsmokers in Project MATCH during and following their treatment for alcohol use or dependence. Results showed that, of those who were nonsmokers at baseline, 15% initiated tobacco use during the 12- month followup period, most beginning during treatment. Smoking initiators' rates of tobacco consumption increased significantly between the 3- and 15-month followup assessments. These results suggest that smoking initiation during substance abuse treatment may be important to monitor and that efforts to help smoking initiators may be warranted.