Dr. Katrin Sangkuhl is a scientific curator at PharmGKB, the online pharmacogenomics knowledge base (www.pharmgkb.org). In this tutorial, Dr. Sangkuhl gives an introduction to the topic of pharmacogenomics - the impact of genetics on drug response. She reviews several pharmacogenetics examples, including codeine/CYP2D6 and clopidogrel/CYP2C19, and provides an overview of the PharmGKB website. The tutorial ends with a description of the clinical relevance of pharmacogenomics testing.