This paper empirically tests the association between recently adopted state-level clean indoor air laws and the smoking behaviour of Mexican men and women. To deal with the problem of highly correlated policies across venues, I construct an index of clean indoor air policies that measures the degree of strictness of smoking restrictions in different locations and the level of enforcement of the laws. Matching policies to individual-level data from the National Health Survey 2006, I find that more comprehensive laws are not associated with the decision to smoke, but are negatively related to daily consumption of cigarettes by men. More specifically, a one unit increase in the index is associated with 3.9 fewer cigarettes smoked a day. The results that test for policy endogeneity show that states with higher intensity of smoking were not more or less likely to pass more comprehensive laws, which suggests that restrictive clean indoor air policies might have been effective at reducing the number of cigarettes smoked by Mexican men who smoke.