A healthy Thai male was found to have an abnormal hemoglobin moving faster than Hb A in starch-gel electrophoresis, in addition to the normal hemoglobin constituents. The abnormal hemoglobin constituted 28% of the whole hemoglobin. The subject was asymptomatic and had normal hematologic findings. Structural characterization revealed that the amino acid substitution wasα56 Lys→Thr. This variant has never been described previously and it is named Hb Thailand.