Objective: Hysteroscopy is the most accurate method for diagnosing intrauterine pathologies related to abnormal blee ding and infertility. The accuracy of three-dimensional (3D) ultrasonography and hysteroscopy were compared in identifying uterine cavity abnormalities. Material and methods: A total of 139 cases of abnormal uterine bleeding or infertility first had two-dimensional and 3D ultrasound performed before hysteroscopy. Findings on 3D ultrasound and hysteroscopy were compared, and sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio were calculated. Results: Mean patients' age was 36.5 (+/-SD 9.04). Three-dimensional ultrasound had a sensitivity of 88%, specificity of 94%, a positive predictive value of 96%, negative predictive value of 84%, likely ratio of 5,5, and accuracy of 90% in diagnosing uterine cavity abnormalities. Three-dimensional ultrasound had a high sensitivity and specificity for polyps (97% and 97%, respectively), congenital uterine malformations (100% and 99%, respectively) and submucous myoma (87% and 100%, respe ctively), but a low sensitivity and high specificity for uterine synechia (41% and 99%, respe ctively). Conclusions: For diagnosing uterine cavity anomalies, 3D ultrasound is a useful tool and could replace diagnostic hysteroscopy for certain conditions, such as congenital uterine anomalies.