Research suggests that stigma plays a major role in discouraging clients from participating in mental health treatment. Because social workers provide a significant amount of such services, this study investigates social work student stigma as a function of their willingness to treat clients with alcohol dependence, nicotine dependence, depression, and Alzheimer's disease. Students' held higher levels of stigma toward nicotine dependent clients and less toward those with depression. Personal histories of depression and student age - but not smoking or alcohol use - were predictive of higher stigma levels towards nicotine dependent clients. Implications for social work are discussed.