Three human leucocyte antigen (HLA) class I loci (HLA-A, -B and -Cw) were typed for the first time at the DNA level in the Corsican population. This analysis was performed on 100 individuals of Corsican origin living in central Corsica (46 individuals) and in south-western Corsica (54 individuals). The genetic structure of these two subpopulations was analysed on the basis of the molecular polymorphisms of the HLA-A, -B and -Cw genes. A phylogenetic and a haplotypic analysis were performed. The genotypic analysis did not detect genetic differentiation. Examination of the allelic and haplotypic frequencies did, however, reveal some significant differences between the two zones. Similarities with the Sardinian population were found, and were particularly evident in the south-western sample. However, Corsica has probably been subject to greater West European influence, which can be seen in the Corte sample (Haute Corse).