Background Although European Society of Urogenital Radiology proposed the potential of multiparametric magnetic resonance imaging (MP-MRI) as a tool in the diagnostic pathway for prostate cancer (PCa) and published a unified scoring system named Prostate Imaging Reporting and Data System (PI-RADS version 1), these still need to be validated by real-life studies. Objective To evaluate the role of MP-MRI in detection and prediction of PCa. Methods Patients with clinical suspicion of PCa who underwent prebiopsy MP-MRI from 2002 to 2009 were recruited. MP-MRI results were retrospectively assigned as overall scores using PI-RADS by two radiologists. Patients were followed and the end point was the diagnosis of PCa. Receiver operating characteristics (ROC) curve was performed to test diagnostic efficacy of MP-MRI, under results of biopsy within three months. The cox proportional hazards model was used to identify independent variables for the detection of PCa. Results Finally, 1113 of the 1806 enrolled patients were included for analysis. The median follow-up was 56.0 months (1-137 mo). For 582 patients biopsied within three months, area under the curve for the detection of PCa with MP-MRI was 0.88 (95% confidence interval [CI], 0.75-1.00) in group of baseline prostate specific antigen (PSA) 0.01-4.00 ng/ml (n = 31), 0.90 (95% CI, 0.84-0.95) in PSA 4.01-10.00 ng/ml (n = 142), and 0.91 (95% CI, 0.87-0.94) in PSA > 10.00 ng/ml (n = 409), respectively. In the cox model adjusted for age and baseline PSA level, for the detection rate of PCa, compared with PI-RADS 1-2 (reference), the hazard ratio was 6.43 (95% CI, 4.29-9.65) for PI-RADS 3, 18.58 (95% CI, 13.36-25.84) for PIRADS 4-5 (p < 0.001). Conclusions Prebiopsy MP-MRI with PI-RADS is demonstrated as a valuable diagnostic and predictive tool for PCa.