Transrectal sonography was used to provide intraoperative guidance for dilatation and curettage and placement of intrauterine tandem apparatus in 20 patients in whom the external cervical os could not be visualized adequately. Transrectal sonography was found to be useful in providing guidance for these procedures and at the same time helped avoid uterine perforation. This method also was used during cerclage placement in two patients who had undergone several conizations. Transperineal sonography was used in three patients whose area of abnormality was best approached transperineally. These cases included transvaginal biopsy of a metastatic trophoblastic tumor and one guided aspiration of a perirectal abscess after pelvic exenteration. The potential advantages and pitfalls in the intraoperative use of transrectal and transperineal sonography for guided intrauterine procedures are discussed and illustrated.