Personalized prescription and pharmacogenomics are related concepts, but are not the same. The 'Introduction' describes the concept of pharmacogenomics, which can be included within personalized prescription, and the role of the Human Genome Project and the Food and Drug Administration in promoting advances in these concepts. In the author's comprehensive view of personalized prescription, clinicians need to consider genetic, environmental and personal variables when prescribing any medication. Known important genetic variables in specific drug responses can be explored by pharmacogenetic tests. Environmental variables - such as co-medication, herb supplements, foods, beverages and smoking - may be much more important than genetic factors for some drugs. Personal factors such as age, gender or medical illnesses (renal or hepatic insufficiency) may be crucial personal variables in the response to some other drugs. The pharmacological knowledge needed to understand personalized prescription includes pharmacokinetics and pharmacodynamic actions, efficacy and safety, idiosyncratic and dose-related adverse drug reactions, prescriber's role and therapeutic window, and linear versus non-linear pharmacokinetics. The applications of these pharmacological concepts in psychiatry are briefly reviewed. Risperidone personalized prescription is provided as an example by describing personalized risperidone selection and personalized risperidone dosing. The future of pharmacogenomic tests and personalized prescription in psychiatry is briefly summarized.