Prostate cancer (PCa) is the most common cancer and the second leading cause of cancer-related death in men. Previous studies have shown that the poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors (PARPis) improve the treatment response of patients with metastatic castration-resistant PCa (mCRPC). However, the efficacy and safety of various PARPis in mCRPC patients remain unclear, presenting a significant challenge for clinicians when making treatment decisions. To address this, this study conducted two indirect comparisons to evaluate the efficacy and safety of four PARPis (olaparib, niraparib, rucaparib, and talazoparib) in patients with mCRPC.