An empiric evaluation of a policy ending smoking in a large urban medical center was conducted. The study included a prospective cohort tracking of employees to measure changes in smoking behavior, environmental fires, smoking-related litter, and environmental tobacco pollution exposure. A 25% decrease in employee smoking prevalence was found (21.7% vs 16.2% before vs after policy implementation, respectively). The daily number of cigarettes reportedly smoked by employees who continued smoking and the total number smoked at work decreased across all occupational categories by an average of 25%. Significant reductions were noted in the level of public smoking and the amount of cigarette remnants. Nicotine vapor concentrations decreased significantly in all areas except restrooms. These findings suggest that visible smoking and environmental tobacco smoke exposure can be markedly decreased by instituting a policy eliminating smoking in a large medical center.