The primary aim of the present review was to summarize the findings of genetic studies conducted on problem and pathological gambling. Literature searches were conducted using PubMed, Medline and the HuGE Navigator databases using the keywords 'gambling' and 'genetic*'. The literature searches identified 21 empirical studies that had analyzed data from eight independent samples. Empirical research utilizing twin data accounted for eight of the studies, while gene association data were presented in 13 studies (including one genome wide-association study GWAS study). Twin studies emphasized the significant role of genetic and individual environmental factors in problem and pathological gambling. Gene association studies primarily reported the involvement of the dopaminergic and serotonergic systems. Despite the relatively low number of genetic studies, the data clearly indicated the genetic vulnerability of problem and pathological gambling. Studies to date have mainly investigated and verified the role of factors reported to be important in other types of addiction, and it is suggested that pathological gambling should be included as a subtype of 'Reward Deficiency Syndrome' (RDS). It is concluded that future research should attempt to identify possible gambling specific susceptibility factors.