Intrathoracic extramedullary haemopoiesis is a rare condition accompanying chronic haematologic diseases. A 25 year old male beta-thalassaemia intermedia patient with bilateral posterior mediastinal masses is reported. Computed tomography and magnetic resonance imaging provide detailed information for evaluation of thalassaemia and similar haemolytic diseases. In geographic areas where thalassaemia is prevalent, to avoid unnecessary surgical interventions, extramedullary haemopoiesis should be considered in differential diagnosis of patients who have chronic anaemia with asymptomatic intrathoracic tumours.