Purpose: Numerous studies have produced conflicting findings regarding the efficacy of statins in prostate cancer treatment. Our objective was to examine the correlation between statin usage and clinical outcomes in Taiwanese men with de novo metastatic prostate cancer. Materials and Methods: We identified patients diagnosed with de novo metastatic prostate cancer from the Chang Gung Research Database spanning the years 2007 to 2020. To minimize confounding bias, we employed the inverse probability of treatment weighting (IPTW) method. Clinical outcomes were assessed using IPTW-adjusted Kaplan-Meier curves. Multivariate Cox proportional hazard regression analysis was utilized to evaluate the association between mortality and clinical factors. Results: The study cohort comprised 1,716 statin users and 276 non-users. Patients who used statins exhibited a longer median overall survival (85.4 months compared to 58.2 months; p=0.001) and cancer-specific survival (112.6 months compared to 75.7 months; p<0.001) compared to non-users. The median time to the development of castration-resistant status was similar between statin users and non-users (p=0.069). Multivariable Cox proportional hazards regression analysis, after IPTW adjustment, demonstrated that statin use was associated with improved overall survival. Conclusions Our study indicates that the use of statins following a de novo metastatic prostate cancer diagnosis enhances survival outcomes. However, statins did not appear to delay the onset of castration-resistant status. Further large-scale and long-term studies are warranted to investigate the biological effects of statins in men with prostate cancer.