Protein polymorphism is studied in more than 900 serum samples during different investigations conducted in a Bi Aka Pygmy group. The Gc, Tf and α1-antitrypsin subtype polymorphisms were determined after isoelectric focusing while the haptoglobin α and α2-peptides were studied on PAGE. A high frequency of the Hp2 gene is noted while Hp1F and Hp1S gene frequencies are similar. According to the Gc1S and Gc2 gene frequencies this group falls within the cluster of the melanoderm populations such as the Sara, Bantu and Peulhs. The two subtypes TfC1 and TfC2 are present in this sample. TfC3 is absent. The TfD1 variant frequency is one of the highest observed in African groups. The α1-antitrypsin polymorphism corresponds to the presence of the three PiM subtypes. No other variants are observed, neither PiS nor PiZ. For the first time a highly significant association is described between the TfD1 and Gc1A1 (GcAb) genes. Family pedigrees do not permit the ascertainment of the linkage between the two l