The purpose of this study was to compare the efficacy of three-dimensional Sonography with two-dimensional saline infusion sonohysterography (2D SIS) in evaluation of uterine cavity in infertile patients in reference to office hysteroscopy. Patient and methods: One hundred patients were recruited for the study with assumption to be harboring a uterine lesion. This assumption was made from the history, clinical examination or previous investigations suggesting uterine cavity abnormality including congenital uterine anomalies (Müllerian anomalies), intrauterine adhesions or uterine cavity pathology (polyps, myomas …). All patients underwent 2D sonography, 2D sonohysterography, 3D sonography and office hysteroscopy. Results: The overall result of accuracy of different modalities was 85% for 2D sonography, 97% for 3D sonography and 91% for 2D sonohysterography. The accuracy of different modalities in detection of endometrial polyp was 89.74% for 2D sonography, 92.31% for 3 D sonography and 100% for 2D sonohysterography. The accuracy of different modalities in detection of uterine anomalies was 91.43% for 2D sonography, and 100% for 3D sonography and 2D sonohysterography. The accuracy of different modalities in detection of intrauterine adhesions was 76.67% for 2 D sonography, 86.67% for 2D sonohysterography, but 100% for 3D sonohysterography. Conclusion From our study we could conclude that 2D sonohysterography has an accuracy rate higher than that of 2D sonography which is preceded by that of 3D US. So, saline infusion may not be needed if 3D US machine is available.