Although campaigns promoting organ donation have proved their effectiveness, increasing the number of people who explicitly agree to become donors is still difficult. Based on the social marketing notion of persuasive technology, we reasoned that it was timely to focus on the design of this persuasive technology and to analyze its contribution in particularly challenging contexts such as organ donation. More specifically, the originality of the present study lay in the way we linked the field of persuasive technology to the theory of social representations, and combined them with an analysis of the ergonomic aspects of interface layout. This study had two complementary goals. The first was to determine whether the sociocognitive salience of the central elements of social representations (i.e., the most frequent and important themes related to the subject—here, organ donation—for individuals), can be used to achieve persuasive outcomes. The second was to determine whether interface layout, in terms of information location and background characteristics (color and contrast), can strengthen the persuasive impact. University students ( N > 200) were exposed to a computer screen displaying a message involving either central or peripheral elements of the social representations of organ donation (status), placed either in the middle or on one side of the screen (location), and shown against either a white or a blue background (background). Eye-tracking data were recorded, in addition to self-reported data. In line with the elaboration likelihood model, results showed that participants who were exposed to central (vs. peripheral) elements of the social representations of organ donation followed the central route in processing information. Moreover, they had stronger attitudes, and more of them stated that they were actual organ donors. Importantly, however, at least for some variables, these status-related effects were not independent of the interface layout. More specifically, the persuasive impact of the central elements was enhanced when the information was displayed in the middle (vs. the side) of the screen and when it was displayed on a white (vs. blue) background. We discuss the theoretical and practical issues raised by these results.