Prostate cancer (PCa) is the most common cause of malignancy in males and the third leading cause of cancer mortality in the United States.The standard care for primary PCa with local invasive disease mainly is surgery and radiation.For patients with distant metastases,androgen deprivation therapy (ADT) is a gold standard.Regardless of a favorable outcome of ADT,patients inevitably relapse to an end-stage castration-resistant prostate cancer (CRPC) leading to mortality.Therefore,revealing the mechanism and identifying cellular components driving aggressive PCa is critical for prognosis and therapeutic intervention.Cancer stem cell (CSC) phenotypes characterized as poor differentiation,cancer initiation with self-renewal capabilities,and therapeutic resistance are proposed to contribute to the onset of CRPC.In this review,we discuss the role of CSC in CRPC with the evidence of CSC phenotypes and the possible underlying mechanisms.