This review is based on a presentation given by Dr Newman at the RCPE Genetics Symposium on 20 April 2012.Pharmacogenetics, the study of genetic variation relevant to drug metabolism, is a rapidly evolving area of medicine. This brief review will consider some of the recent advances where inherited genetic variants have been associated with either drug efficacy or toxicity. Examples of where pharmacogenetic testing has been adopted into clinical practice will be provided as well as a look at its likely development over the next decade. Finally, the large increase in genetic testing of tumour tissue samples to predict response to molecularly targeted treatments in cancer will be considered.