Endorectal ultrasound is integral to preoperative staging of rectal cancer in order to select patients for appropriate management options such as preoperative chemoradiation for locally advanced disease or local therapy for early confined lesions. Accuracy of endorectal ultrasound for determining depth of wall invasion ranges from 81% to 94%, with over-staging in 0% to 12% and understaging in 1% to 9% of cases. Accuracy of endoluminal ultrasound for detection of lymph node metastasis ranges from 58% to 80%. Early detection of recurrent cancer using endoluminal ultrasound may allow for potential salvage reoperation. Endoanal ultrasound provides excellent imaging of the anal canal for diagnosis and management of fecal incontinence and perianal sepsis. Ultrasound imaging can confirm suspected injury to the anal sphincter and may identify occult postobstetric injury. Preoperative endoanal ultrasound mapping of complex perianal abscesses and fistulas provides for minimization of exploration and sphincter injury while assuring complete drainage of sepsis.