Accurate assessment of prostate cancer aggressiveness is important for deciding treatment strategy. Functional MRI sequences such as DWI and DCE have been shown to provide information about tumor aggressiveness. Patients with high Gleason scores exhibited lower ADC values. In this study, we evaluated the potential of IVIM imaging to predict histologic prognostic parameters by investigating whether various IVIM parameters correlate with the Gleason score. The result indicates D is the best IVIM parameter for discriminating prostate cancers with low GS from prostate cancers with intermediate or high GS.