An electrophoretically G-like hemoglobin variant, Hb Hoshida, was detected from a ten year old girl and her mother. No clinical and hematological abnormalities were seen in the individuals heterozygous for this mutant gene. Structural studies of this abnormal hemoglobin demonstrated a previously undescribed substitution ofβ43 (CD-2) Glu→Gin. The proportion of the abnormal hemoglobin in hemolysate was 42,1 per cent. The hemoglobin revealed neither instabilities nor functional abnormalities.