Current epidemiologic studies show a high prevalence of prostate cancers. Many patients have low-risk cancers and do not develop clinical symptoms during their lifetime. As the majority of prostate cancers behaves as a chronic disease rather than as a lethal cancer, diagnostic tools, which involve an accurate patient riskstratification as part of a prostate cancer diagnosis are required. This thesis aims to evaluate multiparametric MR imaging and MR guided biopsy in prostate cancer diagnosis and in risk-stratification.