INTRODUCTION: People with mental illness are more likely to smoke and less likely to receive tobacco treatment than the general population. The Addressing Tobacco Through Organizational Change (ATTOC) approach supports organizational change to increase tobacco treatment in this population. We describe preliminary study feasibility and baseline behaviors and attitudes among clients and staff regarding tobacco treatment, and assesse correlates of treatment of smoking. METHODS: Preliminary accrual, engagement, and baseline data are reported from a cluster-randomized trial comparing ATTOC to usual care. Feasibility, thus far, was the rate of site and participant accrual and engagement (eg, participants remaining in the trial). Correlates of assessing smoking, advising cessation, and providing treatment were assessed. RESULTS: Site and participant accrual is 80% (8/10) and 86% (456/533), and engagement is 100% and 82%. "Staff asking about smoking" was reported by 63% of clients and 38% of staff; "staff advising cessation" was reported by 57% of clients and 46% of staff; staff report "assisting clients with any medication" at most 22% of the time, whereas at most 18% of clients report receiving a cessation medication; 59% of clients want tobacco treatment, but 36% of staff think that it is part of their job. "Staff assisting with medications" is related to more training, believing treating smoking is part of their job, and believing patients are concerned about smoking (ps < .05). CONCLUSIONS: This trial of training in tobacco treatment within mental health care is feasible thus far; self-reported rates of tobacco treatment are low and associated with clinician attitudes and barriers. IMPLICATIONS: Evaluation of ways to help address tobacco use treatment in community mental health care is feasible and needed, including the use of technical assistance and training guided by an organizational change approach.