In the context of the rise in importance of social responsibility and the apparent downfall of the credibility of advertisers, this study explores the relationship between the two, looking for a solution that could lead to saving lives. More specifically, the present research investigates the influence of public social advertising on the motivation of individuals to donate blood. It also discusses the effects and persuasive power of several communication approaches, employed by advertisers. The study is based on original qualitative empirical research, involving content analysis of several international blood donation campaigns and a quasi-experiment with an international audience. The value of this book resides in its social importance - a better understanding of the motivations that drive people to donate blood, or stop them from engaging in this behavior. It is a map for communication professionals and students in an area yet uncharted by academic research, as well as a contribution to solving this perpetually current social issue.