Objectives. – Many communication campaigns to encourage people to give blood rely on “save lives” messages, even though there is no experimentalevidence as to the effectiveness of this kind of argument with respect to blood donation. The objective of this study is to test experimentally if it isindeed an effective way to prompt people to give blood, in order for communication campaigns to be evidenced-based.Methods. – One thousand and twenty-two lapsed blood donors were sent, at random, either a standard letter or the same letter containing anadditional “save lives” message. The blood donation center measured intention to donate and actual donor return rate (3%) after 10 months.Results. – Although fewer people in the “save lives” condition said they had no intention to give blood again, the “save lives” letter did not lead tomore donor returns than the standard letter.Conclusions. – Our results suggest that contrary to intuition, campaigns to promote blood donation should not rely blindly on “save lives” arguments.© 2016 Elsevier Masson SAS. All rights reserved.