The actual strategies of rectal neoplasia's treatment needs an evaluation closer to the reality of the tumor stadium. Imagistic paraclinical exams must bring data about tumor relation with the rectal wall and the mesorectal fascia, the lymph nodes and other important structures invasion. In this purpose it was used a pelvic magnetic resonance imaging (IRM) and computed tomography (CT) comparatively with surgical findings and pathological results on 15 patients with benign and malignant rectal neoplasia, 6 men and 9 females. We apreciate that computed tomography is the choice for imagistic approach of urinary system, mesorectal nodes and uterus and that IRM is best in imagistic evaluation of anterior subperitoneal structures and mesorectal fascia. In these cases association of the IRM exam with spiral CT provides best results concerning tumoral staging.