The role of imaging in treatment decision-making for patients with prostate cancer is to characterize the cancer already diagnosed on biopsy, to determine tumor location, to assess tumor volume, and to exclude more-extensive disease. MRI is currently the most established imaging modality for this purpose, with the highest sensitivity and specificity for detection and staging of prostate tumors. The development and wider adoption of active surveillance and focal treatment approaches would also benefit from accurate localization of cancer. As such, 3 T MRI and multiparametric approaches are being developed as tools for the localization and staging of prostate cancer. Men wishing to commence or remain on active surveillance might benefit by having larger cancers identified before embarking on this management strategy. MRI might have its greatest role in patients where there is a discrepancy between PSA and biopsy results suggesting a potential missed prostate tumor.