Second trimester elective abortion is safest when accomplished with cervical dilation and instrumental uterine evacuation (D and E), but this procedure carries with it a risk of uterine perforation and possible intra-abdominal trauma. In order to determine if the routine use of intraoperative ultrasonography reduces the risk of this feared and serious complication, 353 elective abortions at 16 to 24 weeks gestation performed without sonography were compared to 457 in which sonography was routinely employed. All 810 operations were carried out in one clinic using the same operative technique. The routine intraoperative use of ultrasonographic imaging to guide intrauterine forceps during uterine evacuation for second trimester elective abortion resulted in a significant reduction in uterine perforation, the rate declining from 1.4% to .2%. These findings support the routine use of intraoperative ultrasonography for second trimester elective abortion to reduce the incidence of uterine perforation and make the procedure a safer one.