The major advances that have improved our understanding of prostatic disease are a significant revision of prostatic anatomy, the development of serum assays for prostate-specific antigen (PSA), and an improvement in various imaging modalities, with the greatest advances seen in the field of magnetic resonance imaging (MRI). Multiparametric MRI (mpMRI) provides unique information on tissue characteristics as well as anatomical information. It consists of a combination of standard T1-weighted and T2-weighted imaging and functional imaging modalities such as dynamic contrast-enhanced (DCE-MRI), diffusion-weighted (DWI), and MR spectroscopic imaging (MRSI). In patients with prostate cancer, the role of MRI includes detection, localization, staging, determination of cancer aggressiveness, posttreatment follow-up, monitoring the therapeutic effects after therapy, and guiding targeted biopsy. Recently the Prostate Imaging Reporting and Data System using mpMRI has been addressed. As an ongoing living document, it will evolve as clinical experience and accumulated research data.