The stage of the tumor is commonly underestimated prior to radical prostatectomy for carcinoma. Can the growth of clinically localized carcinomas beyond their capsule be predicted with the modern medical imaging techniques (MRI and CT)? On the basis of 30 successive prostatectomies, we conclude that CT is ineffective. On the contrary, MRI seems to be an effective technique for this indication. However, no examination yet is better than clinical assessment.