Activation of the complement system via classical, alternative and lectin pathways leads to formation of the membrane attack complex (MAC, C5b–C9 genes) againsting invading pathogens. This study aims at analyzing polymorphic association of porcine C8a-b (pC8a-b) with hemolytic complement activity in the classical (CH50) and alternative (AH50) pathways. Whole cDNA of pC8a-b genes was sequenced to detect of single nucleotide polymorphisms (SNPs).  Analyzing their genetic potential on hemolytic complement activity was conducted in a F2 DUMI (reciprocal Duroc x Berlin Miniature Pig) population vacinated vaccinated with Mycoplasma hyopneumoniae (MH), Aujeszky disease virus (ADV) as well as Porcine Reproductive and Respiratory Syndrome (PRRS). Total of 16 SNPs within pC8a-b were found in the different breeds of pig such as German Landrace (LR), Duroc (DU), Hamshire (HS), Pietrain (PIE), Berlin Miniature Pig (BMP), and Muong Khuong (MK, a Vietnamese potbelly pig). Many SNPs located on functional protein domains (like TSP1 and MACPF) and cause subtitution of amino acids. Association of a selected SNP in each gene with CH50 and AH50 was not significantly different in a F2 DUMI. However, statistically significant differences were found in interaction of genotypes and immunized time points for CH50 (only pC8b) and AH50 (both genes) (PThis study provided a weak evidence for polymorphic association of the pC8a-b with hemolytic complement activity. It means that C8 may play an important role in binding to other complement components together to enhance immune response effectiveness of the MAC.