Pharmacogenetics (PGX) is the study of how genetic variants influence individual responses to drugs. Although numerous candidate gene studies in epilepsy PGX have been published, to date only two validated associations exist: the association of the *2 and *3 alleles of CYP2C9 with phenytoin metabolism and the association of HLA-B*1502 with serious hypersensitivity reactions to carbamazepine. The advent of novel technologies such as genomewide association studies and next generation sequencing will likely lead to the identification of additional genetic biomarkers. The potential benefits of epilepsy PGX are multiple: epilepsy treatment in individual patients would become more rationalized, clinical trials could be stratified according to patients' genetic profiles and novel therapeutic pathways may be uncovered. Ultimately, it is hoped that PGX will improve the quality of life for people suffering from epilepsy worldwide.