Objective: To determine the characteristic features of the rare hemoglobin (Hb) variant Hb Yaizu to enable laboratory diagnosis of the hemoglobin variants during screening programs. Materials and Methods: Genomic DNA was obtained from the 4 members of a family living in Denizli province, an Aegean region of Turkey. Blood cell counts, hemoglobin composition, hemoglobin electrophoresis ( both alkaline and acid), HPLC analysis, DNA sequencing and beta globin gene cluster haplotypes were done. Results: Hb Yaizu carriers were apparently healthy individuals. Hb Yaizu was slightly faster than Hb S at alkaline pH, but slower than Hb S at acidic pH in hemoglobin electrophoresis. An abnormal hemoglobin peak was observed with a retention time of 4.77 min in HPLC analysis attributed to Hb Yaizu. Two members of the family were heterozygous Hb Yaizu [ beta 79(EF3) Asp > Asn] confirmed by DNA sequencing. The mutation was found to be linked with the Mediterranean haplotype I [+- - - -++]. Conclusion: We have presented the details of Hb Yaizu, a rare hemoglobin variant that may be important to hemoglobinopathy screening programs, although its clinical significance is unclear. Copyright (C) 2008 S. Karger AG, Basel.