ASCO Guidelines provide recommendations with comprehensive review and analyses of the relevant literature for each recommendation, following the guideline development process as outlined in the ASCO Guidelines Methodology Manual . ASCO Guidelines follow the ASCO Conflict of Interest Policy for Clinical Practice Guidelines . Clinical Practice Guidelines and other guidance (“Guidance”) provided by ASCO is not a comprehensive or definitive guide to treatment options. It is intended for voluntary use by clinicians and should be used in conjunction with independent professional judgment. Guidance may not be applicable to all patients, interventions, diseases or stages of diseases. Guidance is based on review and analysis of relevant literature, and is not intended as a statement of the standard of care. ASCO does not endorse third-party drugs, devices, services, or therapies and assumes no responsibility for any harm arising from or related to the use of this information. See complete disclaimer in Appendix 1 and 2 (online only) for more . PURPOSE: To evaluate evidence on germline and somatic genomic testing for patients with metastatic prostate cancer and provide recommendations. METHODS: A systematic review by a multidisciplinary panel with patient representation was conducted. The PubMed database was searched from January 2018 to May 2024. Articles were selected for inclusion if they reported on patients with metastatic prostate cancer who received a germline or somatic genomic test and/or made comparisons between those tests, reported detection rates, prognostic information, or treatment implications. RESULTS: A total of 1,713 papers were identified in the literature search. After applying the eligibility criteria, 14 remained: eight systematic reviews and six clinical trials. RECOMMENDATIONS: Patients with metastatic prostate cancer should undergo both germline and somatic DNA sequencing using panel-based assays. These tests can guide the use of poly(ADP-ribose) polymerase inhibitors, which have a survival benefit in metastatic castration-resistant prostate cancer. In addition, germline testing may have screening implications for additional cancers for patients and cascade testing implications for family members. The data supporting when to perform repeat testing and optimal tissue type to use (eg, primary tumor v metastatic biopsy versus circulating tumor DNA [ctDNA] testing) are more limited, but this panel recommends considering retesting in patients whose results were previously negative or uninformative, and to consider either a metastatic biopsy or ctDNA when a significant change in clinical status occurs. Next-generation genomic sequencing findings that are associated with prognostic only (and not predictive) value should not be used to guide treatment outside of a clinical trial. Additional information is available at www.asco.org/genitourinary-cancer-guidelines .