Background: Germline mutation testing for metastatic prostate cancer patients creates a potential opportunity to personalize targeted therapies to improve treatment outcomes. The goal of this study was to characterize cancer family history, and evaluate treatment outcomes, in mCRPC patients with DNA repair pathogenic germline alterations. Methods: A retrospective study of metastatic PCa patients at Tulane Cancer Center identified 246 patients undergoing germline testing using panels (30-80 genes) (Color.com or Inviate.com). Clinical annotations included family history, life-extending treatments, and treatment duration. Statistical analyses including chi-square and Wilcoxon Rank Sum. Results: In the 246 patients tested for germline mutations, 27 patients (11.0%) had ≥1 DNA repair germline pathogenic mutation (BRCA2 = 11, BRCA1 = 3, CHEK2 = 5, ATM = 3, NBN = 1, PMS2 = 2, MSH2 = 1, PALB2 = 1) while 219 patients (89.0%) possessed no pathogenic mutation in these genes. Patients with a DNA repair pathogenic mutation were more likely to have > 2 family members affected by cancer, regardless of cancer type or degree of relationship (p = 0.04). In the DNA repair population, 5 pathogenic patients had no family history of cancer (18.5%, n = 5). Patients were more likely to have a germline alteration if they had 1 or more first degree relatives affected with breast cancer (p = 0.00001). Median lines of life-extending treatments to date between the pathogenic and non-pathogenic population were equal at 2. There were no significant differences in treatment duration for abiraterone (p = 0.49), enzalutamide (p = 0.99), docetaxel (p = 0.28), cabazitaxel (p = 0.53), carboplatin+docetaxel (p = 0.41), or radium-223 (p = 0.59) between the two groups. Conclusions: In this study, DNA repair pathogenic germline mutations did not affect treatment durations or lines of therapy but these studies are underpowered. The relationship between a family history of breast cancer and a DNA repair pathogenic mutation has not previously been reported.