Thalassemia intermedia is a clinical definition applied to patients whose clinical phenotype is milder than that of thalassemia major. Criteria used to define thalassemia intermedia including age at presentation, hemoglobin or fetal hemoglobin levels and transfusion independence, are unsatisfactory. The possibility of typing the molecular defect allows a retrospective analysis of patients and offers a new tool for the diagnosis of thalassemia intermedia. Nevertheless, because of several factors that interact in the disease expression, the beta-genotype alone is not predictive of the phenotype in all cases. Although benign, the clinical course of thalassemia intermedia is characterized by several complications that can be prevented by an accurate follow-up. The conventional treatment of thalassemia intermedia remains controversial; it is hoped that recent advances in the pharmacological manipulation of hemoglobin switching will offer a therapeutic option in the future, at least to selected patients.