During 1981-1982 and 1983-1984 a population-genetic study has been performed in the Amhara/Tigrai ethnic groups of Northwestern Ethiopia (Gondar). Blood group frequencies are reported for 6 systems (AB0, MNSs, Rh, P, Kell, Kidd), secretor status, haptoglobin, Gc, Gm/Km, HLA-A and -B as well as for the erythrocytic enzyme polymorphisms AcP, PGM1, ADA, EsD, GPT, AK and GLO I. The results are compared with other reports from East Africa and the Arabian peninsula. The mixed caucasoid-negroid gene pool of the Amhara/Tigrai as well as their relations with Arabia are confirmed.