Medical ultrasound has experienced enormous technological progressduring the last decades. 3D-US represents a new technique of imagingowing to its ability to register all three imaging planes simultaneously toreconstruct new planes which are otherwise not visible as well as tovisualize surfaces three-dimensionally. Characterization of surfacefeatures infiltration and precise depiction of volume are all possible. Theaim of the present study was to evaluate the role of 3D in diagnosis ofuterine and adnexal lesions and its superiority over 2D-US, correlatedwith pathological analysis as a gold standard for the final diagnosis. Thisstudy included a random sample of 50 patients with perimenopausalpelvic mass accidentally discovered during routine ultrasoundexamination or symptomatizing ,attending the outpatient gynecologicclinic, aging between 40 and 56 years old. In this study, 37 out of 38patients with fibroids has been correctly diagnosed by 3D-US whereas2D-US detected 35of them (sensitivity 97.3% vs. 92.1%, and specificity97.5% vs. 99.9% respectively).3D-US was able to diagnose 5 out of 6patients polyps, whereas 2D-US diagnosed 2 of them (sensitivity 83.3%,vs. 33.3%, respectively and the same specificity 99.9% for both).3D-USwas able to diagnose 11 of 16 patients with adenomyosis whereas 2D-USdiagnosed 5 of them (sensitivity 68.75%, vs. 31.2%, respectively and thesame specificity 99.9% for both).3D-US was able to diagnose 13 of 16patients with ovarian cysts), whereas 2D-US diagnosed 4 of 16 ovariancysts (sensitivity 81.2% vs. 25% respectively and the same specificity99.9% for both). In conclusion, the present study confirms thesuperiority of 3D-US over 2D-US in diagnosing pelvic masses. 3D U/Scan be used to supplement 2D assessment. Further large-scale studies areneeded to refine and test the scores used to differentiate benign frommalignant lesions.