This article summarizes some experimental and clinical data about genetic aspects of immunologic response in periodontitis. Both the innate and adaptive immunological reactivity can be modified by genetic factors. Many studies have supported the hypothesis of genetic implications in the etiopathogenesis of periodontitis. Genetic polymorphism being emphasized as a distinctively important phenomenon. The particular genotype determines the susceptibility or resistance to periodontal disease. The HLA molecules play a significant role in the progress of immunological response by presenting bacterial antigens to the effector cells of the immune system. On the basis of many studies a genetic test was developed, embracing the polymorphism of genes encoding cytokines and their receptors. Patients carrying the allele 2 of IL-1β gene are six times more prone to periodontal diseases as compared to the allele 1 of IL-1β gene. So, we can expect the new therapeutic protocols.