Since 2004, the 14th of June has been celebrated as World Blood Donor Day every year. This is a day that commemorates the birthday of Karl Landsteiner, who discovered the ABO blood group. This occasion celebrates and thanks volunteer blood donors around the world. 

World Blood Donor Day aims to create wider awareness of the importance of voluntary blood donation and encourage more people to become regular blood donors. The purpose is to attract a large number of new donors on 14 June and also show appreciation of those individuals who voluntarily donate their blood without any reward.