Background: There is controversy over whether testosterone replacement therapy is a risk factor for prostate cancer. Herein, we evaluate whether testosterone deficiency (TD), testosterone replacement therapy (TRT) or 5-alpha reductase inhibitor (5-ARI) therapy affect the risk of prostate cancer. Methods: Data were collected from 224 male patients who had an indication for prostate biopsy: Prostate specific antigen (PSA) greater than 4, PSA-Velocity >=0.75 in a year, hypogonadism with PSA >=1.5, positive digital rectal exam (DRE) and/or positive Transrectal Ultrasonography (TRUS) finding. Each patient was then subjected to a TRUS-guided 10 core prostate biopsy. Results: 25% (3 out of 12) of the patients on TRT were found to have prostate cancer via biopsy and 32.1% (68 out of 212) of patients who did not receive TRT were found to have prostate cancer; insignificant with p = 0.757. Seventeen our of 76 (22.4%) of the patients on 5-ARI treatment were found to have prostate cancer and 36.5% (54 out of 148) of the patients who did not receive 5-ARI were found to have prostate cancer; significant with p = 0.03. There was no significant statistical difference in Gleason grades among patients who were on TRT, no TRT, on 5-ARI and no 5-ARI. Conclusions: Our data suggest that TRT is not associated with increased risk of prevalence or Gleason grade of prostate cancer. 5-ARI therapy is associated with lower prevalence of prostate cancer but with no relationship to Gleason grade.