Between January 1996 and December 2007, 111 patients with prostate cancer underwent radical prostatectomy, including 34 who received preoperative hormonal therapy. In this study, we reviewed 77 patients who did not undergo neoadjuvant hormonal therapy. The mean age was 65.5 years old and followup time was 40.7 months. The clinical stage was T1c in 60 patients, T2 in 16, and T3 in 1. Prostate specific antigen (PSA) at diagnosis ranged from 3.44 to 46.08 ng/ml (mean 10.18). At our institution, PSA failure after surgery was defined as PSA elevation above 0.2 ng/ml. The pathological stage was pT2 in 59 patients, pT3a in 11, pT3b in 7 and pN + (obturator lymph node) in none. The surgical margin was positive in 29.3% of the pT2 patients and 68.8% of the pT3 patients. Sixteen patients (20.8%) had PSA failure. PSA values at diagnosis and pathological T stage were significantly relevant to PSA failure. Patients with PSA failure underwent radiation therapy or hormonal therapy as a salvage adjuvant therapy. The PSA level was controlled well in majority of the patients. Only one patient died of cancer. In conclusion, 33 out of 111 patients who underwent radical prostatectomy had PSA failure. Sixteen of the 77 patients who were not given neoadjuvant therapy had PSA failure. The significant factors related to PSA failure were PSA values at diagnosis and pathological T stage.