Endorectal prostate biopsies by using 2D ultrasound guidance remain the gold standard for diagnosing prostate cancer. However this technique is limited by a low yield knowing that only 20-30% of all prostate biopsies detect prostate cancer. Since a few years it is possible to do these biopsies by using 3D endorectal ultrasound guidance with fusion to MRI images in order to increase the yield. This new technique permits to visualize the exact localization of all biopsies and gives the certitude of a good mapping of the prostate tissue increasing the yield up to 40%. By fusioning images of the MRI with the 3D ultrasound, it is even possible to target suspect lesions visualized on the MRI, which permits to increase the yield up to 100% in favorable cases.