The susceptibility to periodontitis is determined by a complex interplay between bacteria, the immune system, and life-style factors, and is mainly regulated by genes. The genetic factors contributing to the pathogenesis of periodontitis are still not fully defined. The aim of the present review is to summarize and discuss the status of replicated candidate gene and genome-wide association studies (GWAS) in aggressive and chronic periodontitis. Currently, 3 susceptibility genes, namely GLT6D1, ANRIL, and COX-2, have repeatedly been associated with periodontitis in cohorts of sufficient size. Most of the associations have been reported in aggressive periodontitis. Single nucleotide polymorphisms (SNPs) within ANRIL and COX-2 seem to also be associated with chronic periodontitis. Further, SNPs within the IL-10 gene have shown suggestive associations with aggressive periodontitis, and SNPs within DEFB1 with aggressive and chronic periodontitis. Probably, the identified SNPs are “genetic markers” and not causative variants for aggressive and chronic periodontitis.