Abstract: Objective To determine the expression of Bcl2 related protein A1(Bfl-1) mRNA in prostate cancer cell lines and tissues, and to explore the functions of Bfl-1 in prostate adenocarcinoma. Methods RT-PCR, real-time quantitative PCR(Q-PCR)and in situ hybridization (ISH) were used to detect the expression of Bfl-1 mRNA in prostate cancer cell lines, tissues and benign prostate hyperplasia (BPH) tissue samples. The relationship between Bfl-1 expression and clinicopathological parameters was analyzed. Antisense oligonucleotides (ASONs) were used to interfere the expression of Bfl-1 and its effects on prostate cancer cells. MTT was used to detect the survival, morphologic changes of prostate cancer cells was observed by inverted microscope. Results Bfl-1 mRNA, detected by RT-PCR, Q-PCR and ISH, was overexpressed in the androgen-independent prostate cancer cell lines PC-3 and DU145, but not detectable in the androgen-dependent prostate cancer cell line LNCaP and BPH tissue samples (P<0.05). Significantly higher Bfl-1 mRNA levels were observed in higher stage and metastatic prostate cancer cases than those without metastasis or of low stage. ASONs targeting Bfl-1 significantly inhibited androgen-independent prostate cancer cell growth (P<0.05), cell was rounding off or fragmentation. Conclusion Bfl-1 is involved in maintaining the hormone-independent prostate cancer cell growth. Bfl-1 may become a new therapeutic target in advanced prostate cancer.