Diabetes mellitus is a frequent disorder affecting individuals of all ages. In children, adolescents and young adults, but also sometimes in older people, Type 1 diabetes is the consequence of insulin deficiency, resulting from an autoimmune process destroying the insulin producing cells in the pancreatic islets of Langerhans. In the adults and older persons (but sometimes also in young individuals), Type 2 diabetes (non-insulin dependent diabetes) occurs in genetically predisposed individuals and is favoured by weight excess and sedentarity. This form of diabetes is undiagnosed in about 50% of those affected. This concise review surveys the history of diabetes, the current situation and the expected changes in terms of epidemiology, prevention and treatment. The role of the International Diabetes Federation (IDF) whose headquarters are located in Brussels, is briefly described, particularly in the scope of its fight against a disease currently affecting 180 millions people worldwide, a figure likely to reach 325 millions at the 2025 horizon.