Background: The use of advertising to influence social behavior is one element of social marketing campaigns. While it is known that informational appeals are less effective in changing social perceptions and behaviors, the literature presents mixed and inconsistent results of which appeal (i.e. positive negative or both) is more effective in changing social behavior. The purpose of this study is to investigate the effectiveness of positive, negative and a combination of both appeals on young adults’ drink driving perceptions. Focus: This article is related to research and evaluation of the social marketing field. Research Question: Which, if any, of positive, negative or combination of both emotional appeals, is most effective in changing young adults’ drink driving attitudes, norms and intentions and how well do intentions explain behavior? Importance to the Field: The study builds on, and extends previous research exploring the effectiveness of emotional appeals, contributing to the literature by exploring both emotional appeals along the testing of each appeal separately. The research also validates the TRA’s utility beyond previously explored contexts. At a practical level, the research informs the work of advertising message design. It is recommended that, social marketers consider combined emotional appeals approach when designing messages. Methods: Respondents were randomly exposed to one of three emotional appeals (positive, negative or both) and asked to complete a questionnaire about their attitudes, norms and intentions to drink drive before and after exposure. Two analyses were used, Partial Least Squares Structural Equation Modeling to validate the Theory of Reasoned Action (TRA), and paired sample t-tests to assess change of perceptions over time between the three groups. Results: First the study found the TRA to have a strong predictive utility in explaining drink driving intentions. Second, the combination of both positive and negative emotional appeals was found more effective in changing drink driving attitudes, norms and intentions of young adults. Recommendations for Research or Practice: The study recommends that, social marketers consider combined emotional appeals approach when designing messages. However, further investigation is required to confirm this recommendation and as in any campaign, pre-testing the advertisements with the target audience is a must. Limitations: The key limitations of the study include the use of non-probability sampling, self-reported data, and varied exposure times. Future research should utilize autonomic measures to accurately assess perceptions and emotions as well as unifying the time of exposure for all emotional appeals.