Aim: The aim of the study was to compare the yield of mean platelet volume (MPV), total prostate specific antigen (tPSA), free prostate specific antigen (fPSA), f/t PSA ratio and complex prostate specific antigen (cPSA) in patients with prostatitis.Material and method: The study was designed in the Kayseri Education and Research Hospital. Ninety-six patients with prostatitis were enrolled retrospectively into the study. Laboratory data were obtained from the computerized patient database. We evaluated the correlation between tPSA, fPSa, f/t PSA ratio, cPSA, MPV and extent and aggressiveness of inflammation in the surgical specimens of patients who underwent surgery for benign prostatic hyperplasia (BPH). Inflammation in the prostatic tissues was scored for extent and aggressivity of inflammation using the grading system designed by Irani et al.Results: The total PSA, fPSa, f/t PSA ratio, cPSA and pre- and post-treatment MPV values of each group did not differ (p>0.05) (Table 1). Also there was no correlation between the histopathological grades and the MPV, tPSA, fPSA, f/t PSA ratio and cPSA of patients. However, MPV values significantly decreased after treatment in all grades of prostatitis (p<0.001).Conclusion: MPV values may be used as an inflammation marker in patients with prostatitis.