Study subjects, 1,470 males and 1,603 females, were junior and senior high school students attending 28 schools in Pennsylvania. They ranged in age from 11 to 19 years, and the sample was predominantly white. Of the total sample, 2,862 or 93 percent were categorizable as smokers or non-smokers. A questionnaire was administered that contained objective items related to demographic measures of class standing, sex, age, race, and school name; opinions concerning exposure to anti-smoking messages; and opinions concerning exposure to pro-smoking messages. For each major area examined, students were asked to indicate whether they had been exposed to the particular message or medium over the past school year. Statistical analysis of data revealed a large majority of teenagers were exposed to anti-smoking messages in schools. Teenagers clearly remembered these messages and were made aware of the dangers of smoking. Anti-smoking messages presented in schools were received more positively by non-smokers, and smokers were frequently bored by anti-smoking messages. Non-smokers were more likely than smokers to believe anti-smoking messages helped people quit smoking. The study showed anti-smoking messages alone were not sufficient to impact the smoking behavior of teenage smokers, due in part to lack of follow-up after anti-smoking messages were presented. Promotional smoking advertisements on billboards or in magazines were very effective in depicting smoking as enjoyable or pleasant to teenagers, and the desire of teenagers to smoke was reinforced by these messages. Many teenagers said pro-smoking advertisements helped people choose cigarette brands, many teenagers were exposed to smokers in television programs and felt people smoking in television programs made other people want to smoke, and anti-smoking messages on television were very effective in making teenagers aware of the dangers of smoking. The authors recommend anti-smoking public service messages include a contact or referral telephone number and address for individuals who desire more information or need additional support in altering their smoking behavior. 12 references and 7 tables