Numerous abnormal hemoglobins (Hb) have been discovered in Thailand, and yet further studies continue to show additional variants not previously described This paper reviews the discovery of two more variants, as well as additional studies on families with unusual combinations of mutations. One proposita had an abnormal Hb with similar electrophoretic mobility to Hb J Sangkok, but tryptic peptide mapping by h.p.l.c., amino acid analysis and protein sequence analysis revealed an abnormal peptide alpha-T9, due to the mutation [alpha 61 Lys-Asn], previously found in Hungary and identified as Hb J Buda. Direct DNA sequence analysis confirmed this result and showed that the mutation occurred in the alpha 1 gene and not the alpha 2-gene. The abnormal Hb in another proposita was shown by peptide mapping protein sequence analysis, and DNA sequence analysis, to be identical to Hb G Coushatta [beta 22 Glu-Ala]. In addition to the above variants, unusual combinations of mutations from two other families were studied namely the combination of Hb E (common in Thailand) with Hb C (common in African populations) and the combination of Hb beta(17)-thalassemia/ beta(41-42)-thalassemia.