Periodontitis is a complex, multifactorial disease and the susceptibility is genetically determined. In the last decade a multitude of research projects on genotyping of patients and controls in search of putative genetic risk factors has been performed. The disease (phenotype) however is also dependent on the presence of environmental and lifestyle factors, and their interaction with the various genes. Many candidate genes have been proposed and studied in relation to periodontitis. Most of the studied candidate genes code for proteins that play a role in the innate immune system. Some variants of candidate genes (gene polymorphisms) in the IL1 gene cluster and the FcgammaR genes are possibly associated with periodontitis. However till today there is no strong evidence for target genes and gene polymorphisms that play a key role in the susceptibility to and severity of periodontitis. Therefore genetic testing for periodontitis is currently not indicated.