The health consequences of exposure to environmental tobacco smoke (ETS) are well documented. Although nonsmokers are generally aware of the health risks of ETS exposure, the majority of nonsmokers are regularly exposed. The most common source of exposure is the workplace. Restrictive workplace smoking policies are being used as a primary means of reducing ETS exposure. However, few studies have focused on the relation between workplace policy and ETS exposure. We performed two studies which examined the relationship between smoking policy, self-reported ETS exposure, and salivary cotinine concentrations. Study I, a pilot study, focused on a workplace-based sample of 106 volunteers; Study 2 examined exposure among 881 nonsmokers in workplace settings. In both studies, more restrictive workplace smoking policies were associated with a lower proportion of nonsmoking volunteers with detectable salivary cotinine. In Study 2, the larger study, the only other variable found to be significantly related to cotinine detection was the presence of smokers in the home. These results suggest that restrictive workplace smoking policies may reduce employees' overall ETS exposure.