AbstractWe have undertaken a large population screening study to identify the molecular basis of hemoglobinopathies in the central Greece region. A total of 845 unrelated β‐thalassemia patients and α‐, β‐, and δβ‐thalassemia carriers have been recruited and screened for mutations in the α‐ and β‐globin gene clusters. The α−MED deletion and the Turkish inversion/deletion are the most frequent genetic rearrangements leading to α‐ and δβ‐thalassemia respectively, contrary to the situation in the rest of the country, while the β −101 (C>T) promoter mutation is surprisingly frequent in the central part of Greece. Our data indicate that determination of mutation frequencies in different regions is vital for accurate provision of genetic services and counseling and for precise estimation of genetic diversity. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.