This thesis aims to increase understanding of New Zealand consumer reactions to messages promoting genetically modified food products (GMFs) and to determine how the manipulation of three persuasion variables, message sidedness, source credibility and inward vs. outward focus impact upon consumer attitudes. To achieve this aim, the study integrated two frameworks, Bredahl's, (2001) determinants of attitudes towards GMFs and Wansink and Kim's, (2001) strategies for educating consumers about GMFs, into a new model. To empirically examine the model, a web-based experiment using a 2x2x2 between-subjects factorial design was conducted. The experiment exposed participants to one of eight treatment groups containing a promotional message for Genetically Modified foods. The participants then completed an on-line questionnaire detailing their responses to the messages. A total of 380 useable questionnaires were collected from a national sample of consumers and analysed using ANCOVA. The results of the study suggest that the outwardly focused, two-sided message was more powerful at lowering perceptions of risks, raising perceptions of benefits and positively influencing attitudes toward the ad than either the one-sided, outwardly focused message, or the inwardly focused messages of either sidedness condition. For purchase intentions individual differences appeared to be of greater influence than message factors.