Objective: We analyzed PSA density in patients who had undergone radical retropubic prostatectomy (RRP) with PSA levels between 4.0 to 10.0 ng/ml and compared these values to histopathological examination. Methods: Between July 1992 and December 1997, we performed 117 radical retropubic prostatectomies for clinically localized prostatic carcinoma. Thirty patients whose serum PSA levels were between 4.0 to 10.0 ng/ml, were selected as the study group among all. No patients received neoadjuvant therapy, including androgen deprivation or radiation therapy. The age, preoperative PSA level (Hybritech Tandem assay), PSA density, transrectal ultrasound and Gleason pattern score of transrectal ultrasound guided biopsy and prostatectomy specimens were examined. Results: The age of the patients ranged from 56 to 76 years and the mean age was 63.83±5.01 years. Preoperative PSA levels ranged between 4.0 to 10.0 ng/ml. The mean value was 7.0 ± 1.60 ng/ml. The follow up period of the patients was between 21 and 78 months. The mean follow up was 49.8 ± 14.79 (median: 51) months. Prostate volume ranged from 18 to 110 cc and mean prostate volume was 44.81 + 23.02 cc (median: 42.50 cc). PSA density ranged from 0.08 to 0.55 ng/ml/cc, mean PSA density was 0.19 ± 0.11 ng/ml/cc (median: 0.15 ng/ml/cc). Using 0.15 PSA density as the cut point, 12 (40%) patients had PSA density <0.15 ng/ml/cc. Of these, radical prostatectomy specimen pathological stage was pT2 in 4 (33%) cases, pT3a in 5 (42%), pT3c in 3 (25%). No patient had lymphatic invasion. PSA density was &ge; 0.15 ng/ml/cc in 18 (60%) patients. Of these, radical prostatectomy specimen pathological stage was pT2 in 7 (39%) cases, pT3a in 8 (44%), pT3c in 3 (17%) and 1 patient (6%) had lymph node positive. The follow up of PSA levels revealed recurrence in 6 (20%) patients. The period of these recurrences: mean time to recurrence was 17.3 + 19.54 (median: 24.5 months) months with a range of 3 and 53 months. Five of 6 patients (83%) had PSA density &ge; 0.15 ng/ml/cc. Conclusion: There is still some controversy regarding the treatment algorithm in cases with prostate cancer and PSA levels between 4.0 to 10.0 ng/ml. Recent studies, have underlined that free to total serum PSA ratio has a higher specificity than PSA density for cases with a PSA levels between 4.0 to 10.0 ng/ml in detecting and screening prostate cancer. But, PSA density has shown to be &ge; 0.15 ng/ml/cc in 60% cases who had undergone radical retropubic prostatectomy for localized prostate cancer and PSA levels between 4.0 to 10.0 ng/ml. Furthermore, 39% of them had organ confined disease while 6% had lymphatic invasion..