This study examined the prevalence of home testing for radon and secondhand smoke (SHS) and associations between testing status and sociodemographic variables. It was a cross-sectional study of the baseline data from a randomized controlled trial to test the effects of a personalized environmental report-back intervention on exposure to radon and SHS in the home. Homeowners (n = 515) and renters (n = 47) were recruited in primary care or community settings using stratification by smoking in the home. Homeowners were randomly assigned to treatment or control; renters were assigned to treatment. Home testing status was determined by completion of short-term radon test kits and passive airborne nicotine samplers. Free test kits were provided to the treatment group. Controls received a coupon for free test kits. Of the 562 participants, 48% tested for radon and SHS. Higher education was associated with increased likelihood of testing. Homeowners and renters in the treatment group were more likely to test than homeowners in the control group. Participants were more likely to test their homes when provided free test kits in person.