People who donate blood at least twice a year get a pin bearing the Thai character for the number 9, but the Red Cross urges citizens to give blood as often as once every three months.

World Blood Donor Day commemorates the birthday of Austrian biologist-physician Karl Landsteiner on June 14, 1868. Landsteiner devised the ABO blood group categorisation system still in use today to ensure safety in blood transfusions.

World Blood Donor Day has been observed annually since 2004 to both boost blood supplies and make the public more aware of the need for donations and the safety of the procedure.