Objective To quantify, the effects of smoke-free workplaces on smoking in employees and compare these effects to those achieved through tax increases. Design Systematic review with a random effects meta-analysis. Study selection 26 studies on the effects of smoke-free workplaces. Setting Workplaces in the United States. Australia, Canada, and Germany. Participants Employees in unrestricted and totally smoke-free workplaces. Main outcome measures Daily cigarette consumption (per smoker mid pet, employee) and smoking prevalence, Results Totally smoke-free workplaces are associated with reductions in prevalence of smoking of 3.8% (95%, confidence interval 2.8% to 4.7%) and 3.1 (2.4 to 3.8) fewer cigarettes smoked per day pet, continuing smoker. Combination of the effects of reduced prevalence and lower consumption per continuing smoker yields a mean reduction of 1.3 cigarettes per day per employee, which corresponds to a relative reduction of 29%. To achieve similar reductions the tax on it pack of cigarettes would have to increase from $0.76 to $3.05 (E0.78 to E3.14) in the United States and from pound3.44 to pound6.59 (5.32 to E10.20) in the United Kingdom, If all workplaces became smoke-free, consumption per capita in die entire population would drop 4.5% in the United States and 7.6%, in the United Kingdom, costing die tobacco industry S1.7 billion and 0 10 million annually in lost sales. To achieve similar reductions tax per pack would have to increase to $1.11 and pound4.26. Conclusions Smoke-free workplaces not only protect non-smokers from the clangers of passive smoking, they also encourage smokers to quit or to reduce consumption.