An investigation was performed on the distribution of the gene and haplotype frequencies of A1A2B0, Rh, MNSs, Lewis, P1, Duffy, Kell-Cellano, Kell-Kp, Sutter, Kidd, Lutheran, Hp, Gc, Tf, C'3, Pi, GLO1, EsD, AcP, 6-PGD, PGM1 (subtypes), PTC, and CB loci, and on ABH-antigen secretion in the native Russian population of four rural districts of Tver' oblast'. The following peculiarities of genetic structure of the studied groups were revealed: a higher incidence of A1, A2, MS, NS, Ns, CDE, cDe, cdE, le, se, and K genes and haplotypes, in comparison to the average for Russians; and a lower incidence of cDE, CDe, cde, Jka, AcPa, AcPc, t, and CB+ genes and haplotypes. The incidence of other studied genes and haplotypes coincides with the average ethnic frequencies for Russians.