The present study examined the effectiveness of an anti-smoking message on processing and persuasion in young adolescents. Data were collected from 112 Greek adolescents 13 to 16 years of age, who were randomly assigned into a control and four experimental groups. All participants in experimental groups read a written anti-smoking message varying on the source’s expertise (expert or non expert) and on the quality of the arguments (12 weak/12 strong arguments). Before and after the experimental manipulation, participants completed questionnaires assessing attitudes towards smoking, intention to smoke, perceived behavioral control, subjective norms, knowledge, and smoking behavior. Repeated measures analyses showed no significant differences between experimental groups (p > .05). All groups perceived they were more informed about smoking after the experimental manipulation. Results are discussed according to planned behavior theory and elaboration likelihood model, for effective anti-smoking messages addressed to adolescents.