Persons with mental illnesses use tobacco at significantly higher and heavier rates than the general population, and suffer greater tobacco- related morbidity and mortality. However, there are few existing tobacco cessation interventions for these individuals. This study examined two tobacco cessation interventions, a telephonic quitline intervention (counseling and nicotine replacement therapy) and a community-based group counseling intervention with adults currently receiving community mental health services. At 6-month follow-up, both groups demonstrated significantly reduced tobacco use, but participants who received both quitline services and the group counseling intervention were significantly more likely to have a 50% tobacco use reduction. Across groups, the overall intent-to-treat cessation rate was 7%. Tobacco dependence, depression symptoms, and psychotic symptoms decreased significantly for all treatment groups, while health and mental health functioning increased. Findings suggest that common community tobacco cessation services are effective for this population.