Pharmacogenetics has the potential to help guide treatment decisions by tailoring appropriate drugs and dosages to patients most likely to benefit. This straightforward clinical goal has led some to suggest that pharmacogenetic testing is free of ethical concerns. However, a number of potential risks and clinical uncertainties arise in considering the use of these new tools in clinical care. We propose a classification of pharmacogenetic tests to identify and prioritize the policy issues that will need to be addressed to ensure appropriate delivery of pharmacogenetic testing. We use the classification framework to consider the benefits and risks associated with ancillary information, timing of testing, and storage and retrieval of pharmacogenetic test results among health professionals. These issues have implications for informed consent and genetic counseling requirements, and for the role of health professionals.