Before pharmacogenetic (PGx) testing has a major impact on clinical practice, two levels of evidence must be generated. First, studies demonstrating the links between genetic variation and response to medications in defined populations are needed, along with development of valid tests to measure these specific variants. Second, studies should be conducted to evaluate whether PGx testing improves health outcomes for patients and whether the decision to test is cost-effective relative to usual care. This latter set of questions is typically of greatest relevance to clinicians and payers, the ultimate gatekeepers for the clinical integration of pharmacogenetics. To date, nearly all of the research efforts and funding for PGx have been focused on the first set of issues-getting the science right. However, now is the time to increase our research efforts on the second set of issues-to improve the PGx evidence base for both clinical and economic decision making.