In the Corsican population, the incidence of β-thalassemia traits is reported to be 3.1%. We have investigated the 2 more important β-thalassemia mutations present in the Corsican population: β0-39 and β+IVS1–110. Seven polymorphic sites in the β-globin gene cluster were analyzed from a sample of 43 non-related β-thalassemia heterozygotes and of 47 nonrelated healthy individuals, from Central Corsica (Corte). Among the 43 Corsican patients analyzed, the nonsense codon is predominant (88.40%), whereas the β+IVS1-110 mutation, the most common of β-thalassemia in the eastern part of the Mediterranean basin, is underrepresented (2.33%). The other individuals did not show positive for the two tested mutations (9.27%). The β0-39 mutation in the studied population shows a strong association with haplotype II (18.7%) and a weaker association with haplotypes I (2.3%) and VII (2.1%). The strong association of the β0-39 mutation with haplotype II was also found in Sardinia, suggesting that the mutation on the two islands have the same origin. In the present study all the data concerning frequencies of the mutations and of sequence haplotypes, support the hypothesis of a western Mediterranean origin of the β0-39 mutation. For the first time, this paper analyzes the association of β-globin gene cluster haplotypes with the 2 more frequent β-thalassemia mutations in an isolated population in the centre of Corsica (Corte), which presents certain genetic peculiarities. However, the analysis of β-haplotypes will be very useful for the genetic epidemiological study in this region. Am. J. Hematol. 78:27–32, 2005. © 2004 Wiley-Liss, Inc.