The trait condition for hemoglobin Tak, was found in a 4-day old newborn Malay who suffered from severe neonatal jaundice. The beta chain of the abnormal hemoglobin was elongated by 11 residues at the C-terminus and had the same structure as reported for Hb Tak. The mother was heterozygous for this abnormal hemoglobin, the father was normal. The mother and child, 4 years later, did not show clinical or hematological symptoms except definitely increased resistance of their erythrocytes to hypotonic saline solutions and slight anisopoikilocytosis. The abnormal gene in the two reported Thai families and in our Malay family may have the same origin.