Objectives. We examined the impact of smoking cessation on weight change in a population of women prisoners. Methods. Women prisoners (n = 360) enrolled in a smoking cessation intervention; 250 received a 10-week group intervention plus transdermal nicotine replacement. Results. Women who quit smoking had significant weight gain at 3- and 6-month follow-ups, with a net difference of 10 pounds between smokers and abstainers at 6 months. By the 12-month follow-up, weight gain decreased among abstainers. Conclusions. We are the first, to our knowledge, to demonstrate weight gain associated with smoking cessation among women prisoners. Smoking cessation interventions that address postcessation weight gain as a preventative measure may be beneficial in improving health and reducing the high prevalence of smoking in prisoner populations.