The purpose of this study was to examine in a systematic, controlled fashion the reactions of smokers to scientifically correct information about the risks of smoking Light cigarettes (about 6-15 mg tar by the FTC method). Random-digit dialing, computer-assisted telephone interviews were used to locate daily smokers of Light cigarettes. In an experimental design, smokers were randomly assigned to listen (n = 293) or not (n = 275) to a persuasive simulated radio message on the risks of Light cigarettes; 108 of those who did not listen to the message in the first part of the interview were played the message in the second part, to evaluate some repeated-measures effects. Those who heard the message were more likely to report that one Light cigarette could give a smoker the same amount of tar as one Regular cigarette and that Light cigarettes were more dangerous: 55% said the message made them think more about quitting and 46% said the message increased the amount they wanted to quit; 42% said that after hearing the message they thought Light cigarettes were more dangerous. Using the Theory of Planned Behavior, structural equation modeling analysis indicated that the message acted to increase intention to quit smoking by increasing the desire to quit smoking. Seventy-three per cent of the smokers agreed that it was important to play such messages widely on the radio; 77% agreed that there should be a warning on packs that vent blocking increases tar; 61% agreed that the location of filter vents should be marked. The majority of smokers of Light cigarettes seem to value being informed that Light cigarettes are as dangerous for them as Regular cigarettes, and this information increases their intentions to quit smoking.