The clinical value of TRS in diagnosis and staging of radiogenic rectal disorders is discussed. TRS was performed on 120 patients with tumours of lower pelvis who were treated by radiotherapy. They were divided in this trial into 2 groups. Group I (n = 113, with a mean interval to radiotherapy of 2 years) including patients who were under a routine control. Group II (n = 7, with a mean interval to radiotherapy of 13 years) including patients with strong local pain of the radiotherapy zone. The sonographic changes were divided into 4 grades (0-III) and verified histologically in group II patients by means of biopsy. A control group (n = 35) was also examined by TRS. The patients of this group were not treated radiotherapeutically. We concluded in our study that TRS in radiogenic rectal disorders, give us a very precise grading of the tumours which in turn, is of great importance in the further therapeutic procedure and in the evaluation of tumour recidives and second malignomas of the rectal wall.