The implementation of pharmacogenomics in clinical practice has increased in clinical oncology practice. Pharmacogenomic germline testing can be used to develop and prescribe safer and more effective medications and treatment regimens that are personalized to patients based on their individual genetic profiles. To properly apply pharmacogenomics to oncology practice, nurses need to have a clear understanding of pharmacogenomics, specifically how to collect DNA specimens, interpret test results, and educate patients about lifelong implications. This article reviews pharmacogenomic germline testing, its use in oncology clinical practice, and how pharmacogenomics can help oncology nurses provide optimal care for patients.