Abstract: Objective To study the effect of androgen deprivation therapy on prostate cancer stem cells in prostate cancer tissues and to investigate the mechanisms of the formation of androgen independent prostate cancer. Methods Eighteen patients were divided into 2 groups, the ADT (androgen deprivation therapy) group and non-ADT group. The proportions of cancer stem cells in preoperative and postoperative prostate cancer tissues were compared with immunofl uorescence. Results In the non-ADT group, the differences of cancer stem cell proportion between preoperative and postoperative specimens were not prominent(3.56±1.33)% vs. (3.78±1.39)%, n = 9, t =-0.686, P = 0.512. But in the ADT group, compared with preoperative specimens, the proportion of prostate cancer stem cells was signifi cantly increased after undergoing androgen deprivation therapy for 3 months (3.44±1.81)% vs. (9.22±1.71)%, n = 9, t = -6.353, P = 0.000. In the tissue adjacent to carcinoma, stem cell markers were also increased after ADT. Conclusion Androgen probably is involved in the differentiation of prostate stem cells or prostate cancer stem cells. The formation of androgen independent prostate cancer may be related to prostate cancer stem cells.