Introduction: This study replicated prior observations of racial differences in smoking cessation in which Black smokers have demonstrated lower smoking cessation rates than White smokers. Methods: The study used data from a smoking cessation intervention and compared White and Black female prisoners (N = 233) on a 10-week intervention of group psychotherapy and nicotine replacement (patch). Generalized estimating equations were used to model smoking cessation across the 12-month follow-up. Results: Compared with an untreated control group, both Black and White smokers benefited from the cessation treatment. However, after controlling for potential confounds, White smokers had significantly higher overall smoking cessation rates across time compared with Black smokers (e.g., 30% vs. 24% abstinent at 6 weeks; 13% vs. 10% abstinent at 12 months). Smoking mentholated cigarettes was not associated with these differences in quit rates. Discussion: Understanding differential treatment responses can lead to the development of more tailored and efficacious smoking cessation interventions that may reduce the morbidity and mortality associated with smoking in prison populations. © The Author 2009. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved.