A molecular-genetic study of 5-HTTLPR and the Stin2 loci of the serotonin transporter gene (5-HTTL) in males of the African ethnic populations Hadza and Datoga, which differ in the level of culturally acceptable aggression, was carried out. The distribution of allele and genotype frequencies of these two loci was established. It was shown that the frequency distribution of genotypes and alleles among Hadza and Datoga in the examined samples is practically identical by the VNTR-polymorphism of both loci. However, the Hadza populations, as compared to Datoga, showed a significant (p = 0.006) increase in the frequency of the transcriptionally less active allele L(G) of the 5-HTTLPR locus. For the first time, the structure of the allelic variant of locus Stin2 with eight repetitions (Stin2.8) is described and established for African populations. The test for independence of the frequency distribution of the alleles of the studied loci showed highly significant linkage disequilibrium among Hadza (p << 0.001) and Datoga (p = 0.021). In analysis of the genotype combinations of two loci, it was revealed that thestudied populations differed significantly by the L(A)L(G) 10/12 genotype (p << 0.001). When combining the genotypes, no significant differences between the populations based on their expression activity were identified. We assume that the identified combined genotypes reflect the effects of similar behavioral traits for both populations.