OBJECTIVE: To compare the diagnostic performance of saline infusion sonohysterography (SIS), transvaginal ultrasound (TVS), and diagnostic hysteroscopy (DH) in the detection of endometrial lesions in symptomatic women.DESIGN: Prospective, comparative study.SETTING: Obstetrics and Gynecology Department of a tertiary academic hospital.PATIENT(S): A total of 105 consecutive women presenting in an outpatient clinic with symptoms of menorrhagia, postmenopausal bleeding, and infertility.INTERVENTION(S): Each patient had TVS, SIS, and DH.MAIN OUTCOME MEASURE(S): The sensitivity, specificity, and positive and negative likelihood ratios (LR+ and LR-) for TVS, SIS, and DH were determined for the diagnosis of endometrial pathology. More specifically, the diagnostic performance of each of these three methods was compared after receiver operating characteristic analysis.RESULT(S): By comparative analysis of the area under the curve, DH was found to have a significantly better diagnostic performance compared to SIS and TVS. In addition, after comparing the receiver operating characteristic curves, DH was found to be significantly more precise in the diagnosis of intracavitary masses than TVS and SIS. However, SIS was more accurate compared to TVS.CONCLUSION(S): Saline infusion sonohysterography appears to be more valuable than TVS in the diagnosis of intracavitary masses (both polyps and myomas).