The purpose of this paper was to review studies on persuasion from the viewpoint of the Elaboration Likelihood Model based on Petty & Wegener (1998). The paper consists of the following four parts. 1. Introduction. 2. Multiple roles for persuasion variables. 3. Source variables: (1) credibility (expertise, trustworthiness), (2) attractiveness/likableness, (3) power, (4) additional source factors related to credibility, liking and power (speed of speech, demographic variables, majority/minority status, similarity to receiver), (5) number of sources. 4. Message variables: (1) message topic, position and style (issue-relevance/importance, position/discrepancy, conclusion drawing, use of rhetorical questions), (2) message content (argument quality, argument quantity, positive versus negative framing of arguments, fear-threat appeals, emotion versus reason in message, one-versus two-sided message), (3) message organization.