This research examines the interplay between message framing (gains vs. losses) and social distance (proximal vs. distal) on intention to adopt two pro-social health behaviors. Experiment 1 revealed that a gain-framed message (benefits of blood donation), associated with the testimonial of a distal person (someone older than the répondent), and loss-framed message (lack of benefits from not giving blood), associated with the testimonial of a proximal person (someone of similar age à the répondent), are the most effective combinations for promoting blood donation. Experiment 2 replicated these results with organ donation and indicated that consumers' comparative optimism moderates these effects.