In the past ten years, the treatment of prostate cancer has undergone remarkable changes. Furthermore, systematic prostate biopsy under transrectal ultrasonography or the measurement of prostate specific antigen has provided significant improvement in the detection of prostate cancer. Considering the increasing detection of prostate cancer, it is very important to clarify prognostic parameters in order to select the optimal treatment of given patients with localized or advanced prostate cancer. Recent statistical analyses showed that tumor volume, lymph node involvement and Gleason score would be significant prognostic indicators in localized prostate cancer. In advanced cancer, the response to the initial endocrine therapy might be a good prognostic parameter in addition to the histopathological features of primary tumors. In order to determine the factors which predict the prognosis of prostate cancer more accurately, the molecular biological approach is now ongoing, and may provide novel parameters for the decision making in the treatment of prostate cancer.