The online-only campaign is being launched following a successful cross-media push featuring a number of celebrities including Carol Smillie and Steve Cram, which ran earlier this year.
The campaign aims to get men over the age of 35, who the National Blood Service has identified as disproportionately important donors, to register to donate blood by leaving an e-mail address for future contact.
The campaign will run on sports, news and finance websites and the ISPs Tiscali, BTOpenworld and Freeserve. Websites include that of the magazine Men's Health, Guardian Unlimited, Gra-nada's ITV-football.com, Cricinfo, Classicfm and Sky-sports.com.
Media planning and buying was handled by interactive @optimedia with creative developed by DLKW Dialogue, the below-the-line arm of Delaney Lund Knox Warren & Partners.