Résumé : An estimation of the incidence and demographic picture of the major hemoglobinopathies in Belgium has been approached through a confidential inquiry sent to 228 pediatric and adult hematological departments. Forty-two percent of responses showed that 417 patients are known in Belgium: 83% with sickle cell disease, 13% with beta-thalassemia (beta-thal) major, 2% with beta-thal intermedia, and 1% with Hb H disease. Twenty-five percent of the sickle cell disease patients and 54% of those suffering from a beta-thal major were older than 20 years. Three hospitals ensure the follow-up of 70% of the patients and are situated in Brussels, Belgium; a follow-up of less than 20 patients was reported at 21 centers. These results confirm that sickle cell disease is the major hemoglobinopathy in Belgium; it concerns mostly pediatricians but adult hematologists are also confronted with these pathologies. Therefore, it is necessary to implement integrated programs of prevention and treatment.