This research investigates the influence of messenger sources and message appeals. The effects of interactions of messenger sources and appeals were found regarding (a) attitudes toward radio anti-binge drinking Public Service Announcements (PSAs); (b) attitudes toward binge drinking; and (c) intention to binge drink. The superiorities of matches between the sources and appeals were also examined using match-up hypotheses. College students (N=251) participated in a 2 x 2 (sources: medical expert vs. peer spokesperson x appeals: belief vs. evaluative) factorial design online experiment. Four transcribed radio PSAs were created and evaluated by MANCOVA with four covariates. The primary results were that there were conditional impacts of a similar source (peer) on creating favorable attitude towards the PSAs. Messages were more effective when there is consistency between sources and appeals (ex: expert/belief and peer/evaluative). The Fishbeins expectancy-value theory was used to assess attitudinal changes and discussed in its usefulness and application in health-related campaigns.