Blunt traumatic injury to the urogenital region in the prepubescent girl is commonly evaluated in pediatric emergency departments (ED). The purpose of this study is: 1) to establish recommendations for an accurate, painless (both physically and psychologically), and timely diagnosis, and 2) to determine whether the ED examination can accurately determine the extent of the injury. Over a 24-month period (January 1991 through December 1992), 22 girls with blunt trauma to the urogenital region (mean age 5.7 years, range 2-9 years) were retrospectively evaluated. Initial ED evaluations were by both an emergency physician and a pediatric surgeon. All 22 patients underwent an examination under anesthesia (EUA) in the operating room to evaluate the extent of the injury and to repair the injury as needed. Follow-up was obtained in all patients and averaged 18 months. The findings at EUA demonstrated a significant disagreement with the preoperative ED evaluation. In only five patients was there agreement between the preoperative ED assessment and the findings during the EUA (24% concurrence). Thus, 16 patients (76%) had injuries of greater extent than was appreciated during the preoperative examination in the ED. Partial or complete disruption of the perianal sphincters occurred in six patients (27%) and was unrecognized preoperatively in each. Twenty-one of the 22 patients required suture repair of lacerations, the remaining patient did not require surgical therapy. Three patients had contusions or lacerations to the urethral area requiring repair and/or prolonged bladder catheter drainage for two to 14 days (average seven days). The average hospital stay was 19.3 hours. There were three minor wound complications following surgery: two required repeat EUA with suturing or cauterization, and one required no further therapy. This study clearly demonstrates that the ED examination, by both emergency physicians and pediatric surgeons, of young girls who have suffered blunt urogenital trauma grossly underestimates the severity of injuries when compared to the EUA in the operating room. EUA is safe and allows early discharge with minimal psychologic sequelae. Recommendations for mandatory EUA are made.