Objectives: To investigate predictors of tobacco abstinence among smokeless tobacco (ST) users. Methods: Logistic regression analyses assessed characteristics associated with tobacco abstinence among ST users receiving bupropion SR. Results: Older age was associated with increased tobacco abstinence in both placebo and bupropion SR groups at end of treatment and one year. Abstinence was lower at one year for subjects with a history of major depression. At end-of-treatment, a 2-way interaction was detected suggesting bupropion SR may be efficacious for subjects with other household tobacco users. Conclusions: Younger ST users and those with a history of depression are less likely to quit ST use.