Analysis of polymerase -chain - reaction - amplified (PCR) /beta-globin DNA with allele-specific oligonucleotide (ASO) probes reveals an extremely heterogeneous spectrum of /beta-thalassemias in Mediterranean Turkey. However, about 15% of §-thalassemia mutations cannot be identified with this approach. Combination of selective amplification of certain regions of the /beta-globin gene with denaturing gradient gel electrophoresis (DGGE) allowed us to rapidly localize several of these mutations to specific regions of the gene that were amplified and directly sequenced. We believe that the combination of DGGE and direct sequencing techniques for determination of PCR-amplified genomic DNA represents a valid alternative to the 'ASO Probes' approach, particularly in Antalya, a province on the western Mediterranean coast of Turkey, where §-thalassemia mutations occur in a heterogeneous spectrum.