Three abnormal hemoglobins identified as G by their electrophoretic mobility and performance on resin chromatography have been discovered in three healthy unrelated Negro individuals in Texas. These three G hemoglobins have been shown to belong to the same molecular species and to have a substitution in the 43rd residue of the β chain. Glutamic acid, which is present in this position in hemoglobin A, has been replaced by alanine in hemoglobin G. According to the recent suggestions on nomenclature of abnormal hemoglobins, hemoglobin GGalveston may be formulated as α24β243 Glu→ ala. Moreover, it has been shown that the following hemoglobins belong to the same molecular species: hemoglobin GGalveston, hemoglobin GPort Arthur, and hemoglobin GTexas. This alteration is the first to be described in the fifth tryptic peptide of the β chain of human hemoglobin and differs from all abnormal hemoglobins previously reported.