The health hazards caused by exposure to environmental tobacco smoke (ETS) are well established. Workplace exposure to ETS is strongly influenced by the types of workplace and smoking policy-total bans on smoking have become common in many countries. Blue-collar and service workers are more likely than other types of workers to be exposed to ETS in the workplace. Smokers who are employed in workplaces with smoking bans are likely to consume fewer cigarettes per day, are more likely to be considering quitting, and quit at an increased rate compared with smokers employed in workplaces with no or weaker policies. Despite substantial progress in protecting workers from ETS, additional efforts are needed in areas that include attention to exposure among blue-collar and service workers; policies in workplaces with a limited number of employees; and studies of enforcement, effects on smoking cessation in multiple settings, and cost-effectiveness.