Mahidol Day is observed in Thailand every September 24 to commemorate the death anniversary of Prince Mahidol Adulyadej, who is recognized as the father of modern medicine and public health in the country. Born on January 1, 1892, Prince Mahidol contributed significantly to improving public health through his education at Harvard and his collaboration with the Rockefeller Foundation for technical and financial support. He passed away on September 24, 1929, from kidney disease. In honor of his contributions, Mahidol Day was officially designated to celebrate his legacy. Additionally, in 1992, King Rama IX established the Prince Mahidol Award, which recognizes outstanding achievements in medicine and public health promotion. The observance serves as a reminder of Prince Mahidol's impact on Thailand's healthcare system and public health education.