The alternative to immediate radical treatment of prostate cancer is active surveillance, to which an estimated 30% of new patients with prostate cancer could be directed on the basis of risk classification. Active surveillance is based on repeated PSA measurements, digital rectal examination, repeat biopsies, and increasingly also on MRI. The most important prognostic factor in prostate cancer is still the Gleason score, forming the basis for the new grade group classification with the purpose of rendering active surveillance of prostate cancer a form of treatment that is more easily acceptable for the patients. MRI enables a more reliable selection of low-risk prostate cancer patients for active surveillance. The significance of MRI as a surveillance tool remains unclear.