This work was finalized to compare the diagnostic potential of Diffusion Tensor and Diffusion Kurtosis Imaging in discriminating between low- and high-risk prostate cancer (Pca). Maps of Mean Diffusivity (MD), apparent Kurtosis (K) and apparent diffusion coefficient (D) were obtained from DWIs of 24 patients with different tumour grade. K maps better highlight differences between periferal PCa, PCa and benign tissue. In particular K discriminates between low- and high-risk PCa with a higher statistical significance compared to that of MD. DKI can improve the accuracy of the current PCa diagnosis providing a useful tool for PCa detection and grading.