ABSTRACT: PURPOSE:To determine the clinical significance and correlation between the Prostate Health Index (PHI) and Gleason score in patients with a prostate-specific antigen (PSA) value of 2.5-10 ng/mL. MATERIALS AND METHODS:This retrospective analysis included 114 patients who underwent biopsy after completion of the PHI from November 2018 to July 2019. Various parameters such as PSA, PHI, PSA density, free PSA, p2PSA, and %free PSA were collected, and correlations with biopsy Gleason score and cancer detection rates were investigated. RESULTS:Baseline characteristics were comparable between PHI groups (0-26.9 [n=11], 27.0-35.9 [n=17], 36.0-54.9 [n=50], and ?55.0 [n=36]). A total of 37 patients (32.5%) were diagnosed with prostate cancer, and 28 (24.6%) were diagnosed with clinically significant prostate cancer (CSPC, Gleason score ?7) after prostate biopsy. The cancer detection rate gradually increased with a corresponding increase in the PHI (18%, 24%, 30%, and 44%, respectively). The same pattern was observed with detecting CSPC (0%, 18%, 26%, and 33%, respectively). There was no CSPC in the groups with PHI <27.0, and Gleason score 7 began to appear in groups with PHI ?27.0. In particular, patients with Gleason score 8 and 9 were distributed only in the groups with PHI ?36.0. CONCLUSIONS:The diagnostic accuracy of detection of CSPC could be increased when prostate biopsy is performed in patients with a PHI ?36.0. In this study, there was a clear Gleason score difference when the PHI cutoff value was set to 27.0 or 36.0.