Linkage disequilibrium is a characteristic of MNSs blood group system which performs more frequent association of linked alleles than it is expected in comparison with their allelic frequencies. Measure of linkage disequilibrium is the difference between expected and actual genotypic frequencies which is stated in coefficient of linkage disequilibrium. The purpose of this study was to fortify existence of linkage disequilibrium phenomenon inside MNSs blood group system in population of South Backa in comparison with calculated allelic frequencies. Blood group typing in MNSs system included 1,000 healthy nonrelated persons where allelic frequencies, expected and actual genotype frequencies had been calculated, as well as the differences between them. Results of investigation showed that allele has the highest allelic frequency (0.672), S allele has the lowest frequency (0.33), the highest expected frequencies are calculated for Ms/Ns (Ms/NS) (0.218) and Ms/Ns (0.2235) genotypes, while the actual frequencies are highest for MS/NS (Ms/NS) (0.184), Ms/Ns (0.193) and Ns/Ns (0.153) genotypes. Statistically significant difference between expected and actual genotypic frequencies occurs for Ms/MS and Ns/Ns genotypes, which means that S and M and N and s alleles are more frequently associated and prove the existence of linkage disequilibrium phenomenon in population of South Backa.