This study was the first to examine rural youth's responses to ten television and radio tobacco countermarketing ads aired during a 13-week field campaign conducted in a U.S. Northern Plains state. A post-campaign survey of 391 girls and boys aged 12-17 years and including 58 American Indian youth provided information about their confirmed recall (CR) of the ads; and for recalled ads, their ratings of the ads' perceived effectiveness (PE). Results were that controlling for age and smoking risk, both American Indian and white girls and boys had the highest CR for the television ad Artery and for the radio ad ABC. Artery shows fatty deposits being squeezed from a deceased smoker's aorta, and ABC presents a former smoker speaking through his electro-larynx. Among the television ads, PE ratings were highest for the ad Artery in both boys and girls. Among the radio ads, boys rated ABC highest, whereas girls rated Joe DoBoer highest-an ad that discusses mouth lesions that developed from using smokeless tobacco. An analysis of race/ethnicity differences in PE for the ad Artery and ABC indicated American Indian and white youth considered these ads equally effective. These findings indicate certain TV and radio ads depicting graphic health harms from tobacco-especially the TV ad Artery and the radio ad ABC-are highly recalled and perceived as effective by both American Indian and white girls and boys from a rural region. Future research is needed to better understand which individual- and media-level factors increase the likelihood that anti-tobacco ads will be effective in reducing youth tobacco use.