We produced polyclonal antibody against human androgen receptor (hAR) by means of immunizing a rabbit with hAR fusion protein that was expressed in E. coli. In Western blot analysis, this antibody, NH27, recognized two protein bands at the site of 110 kDa and 107 kDa in androgen-independent human prostatic cancer cells (PC-3), transfected with full-length hAR expression plasmid DNA and at the site of 114 kDa and 108 kDa in androgen-dependent human prostatic cancer cells (LNCaP). In immunohistochemical examination with NH27, the nuclei of epithelial and stromal cells in human benign prostatic hyperplasia were mainly stained as did with AN1-15, commercially available hAR monoclonal antibody. Titer of NH27, however, was about five times more high than that of AN1-15. In prostatic cancer cells the nuclei were stained with NH27 as did with AN1-15. Intensity of staining was various between the nuclei of cancer cells. The polyclonal antibody, NH27, produced in the present study is useful in investigating the characterization of AR in androgen-dependent and -independent prostatic cancers.