Preoperative evaluation of the depth of invasion in the rectal wall as well as the presence of regional metastatic nodes are considered important factors in order to decide surgical treatment as well as prognosis in cases of cancer of the rectum. This investigation was carried out in order to establish how usefull transrectal ultrasound was for the pre-operative evaluation of cancer of the rectum. We studied 78 patients with different ano rectal pathology, among them 40 patients with confirmed ADC of the rectum that were completely studied and had ultra sonographic as well as surgical and pathological staging using TNM classification. Confiability indicators of transrectal ultrasound when compared with pathology findings, showed a sensibility of 100% in T1-T2 and T4; in T3 lesions sensibility was 76%. Specificity was between 94% and 100% in all stages. We believe that trans-rectal ultrasound is a usefull, precise and reliable diagnostic tool, for staging purposes of rectal carcinoma.