This study evaluated the long-term impact of genetic susceptibility biomarker feedback on smoking behavior change and symptoms of depression in 426 male and female smokers. Smokers were randomized to one of three smoking-cessation interventions: minimal contact quit-smoking counseling (QSC), QSC + exposure biomarker feedback (EBF), and QSC + EBF + biomarker feedback about genetic susceptibility to lung cancer (SBF). The logistic regression model for quit attempt revealed a significant main effect for treatment such that participants in the SBF group were more than two times more likely to make a quit attempt than participants in the QSC group. There was not a significant difference between EBF and QSC participants. The results also revealed a significant effect for baseline stage of change. Those smokers in the preparation stage at baseline were more than three times more likely to make a quit attempt over the 12 months following treatment. The models for 30-day cessation and follow-up smoking rate revealed no significant main or interacting effects for treatment. A repeated measures analysis of variance revealed a significant main effect for time, indicating that an initial increase in depression in the genetic susceptibility group was not maintained over time. Genetic susceptibility feedback has the intended effects on motivation to quit, but it may need to be delivered within a more intensive smoking-cessation treatment for the heightened motivation to translate into smoking cessation.