Radon and cigarette smoking have synergistic effects on lung cancer risk. Electric utility company bill stuffers offered free radon test kits to households with at least one smoker. Participating households (n = 1364) were randomized within a 2 x 2 design to evaluate the main effects of brief telephone counseling and a targeted video on smoking cessation and the establishment of new household smoking bans. Phone counseling was associated with cessation at 3-month follow-up but neither intervention led to 12-month or sustained cessation. While neither intervention had a significant effect on new bans, there were trends in the predicted direction and the combination of the two significantly increased new bans compared with no intervention. The presence of children in the household was associated with new bans. While few households had high levels of radon, such levels were associated with radon mitigation behaviors. Together with a previous study, these results suggest radon risk is a useful and inexpensive way to engage smoking households in risk reduction behaviors, especially the institution of household smoking bans.