Endorectal ultrasound is proving to be a very accurate method for the preoperative staging of cancer. The tumor penetration depth is assessed with an accuracy of more than 90% for all T stages. The preoperative endosonographic evaluation of lymph nodes is superior to other imaging modalities, being more than 80% accurate in comparison to CT and lymphoscintigraphy. It is relatively easy to perform and inexpensive compared with other imaging modalities. It has proved its influence on decision making, selection for local therapy, planning of radiotherapy and reoperation of early tumor recurrencies.