National Internal Medicine Day is observed worldwide every October 28. Established in 2019 by the American College of Physicians and the National Day Calendar, this day celebrates the professionalism and contributions of internal medicine specialists, known as internists, to the healthcare system. Internists focus on the prevention, diagnosis, and treatment of internal diseases in adults and are recognized for their expertise in managing complex chronic conditions. They work in various settings, primarily hospitals, and may also engage in teaching, research, and administrative roles. The day highlights the significant advancements made by internists in medical research and patient care, acknowledging their vital role in healthcare. Notable internists have contributed to groundbreaking innovations such as the development of the cardiac risk index and research on chronic illnesses.