Abstract： Objective To investigate the diagnostic value of conventional and dynamic gadolinium-enhanced T1-weighted (T1W) MRI in benign and malignant endometrial polypoid lesions. The pathologic basis of MRI features was also evaluated. Methods The conventional and dynamic contrast enhanced MRI features in 48 cases with clinicopathologically-proved endometrial polypoid lesions were retrospectively analyzed, including 26 cases with malignant tumors (23 eases with endometrial carcinoma and 3 cases with endometrial sarcoma) and 22 cases with benign polypoid lesions (12 cases with endothehal polyps and 10 cases with submucons leiomyomas). The occurrence probability of central fibrous core, intratumoral cysts and intact junctional zone were evaluated by Fisher's exact test. Results Benign and malignant endometrial polypoid lesions had specific characteristics on MRL Endometrial carcinomas usually appeared as homogeneous intermediate or slightly high signal-intensity masses on T2-weighted images, and relatively homogeneous hypedense masses on contrast-enhanced images with myometrial invasion (P < 0.05). An irregular central fthrous core and small non-enhanced intratumoral cysts were seen more frequently in endometrial polyps (P < 0.05) than others. All 3 cases with uterine sarcomas showed obviously inhomageneous intensity on T2WI and demonstrated areas of early and persistent marked enhancement.Submucous leiomyomas demonstrated isodense or slightly low-density masses with defined outline on T2 WI and the endomerium was displaced. The diagnostic sensitivity, specificity and accuracy of malignant polypoid masses were 92.3% (24/26), 83.3% (20/24) and 95.8% (46/48) respectively. Conclusion Conventional and dynamic contrast-enhanced MRI are valuable in characterizing the benign and malignant endometrial polypoid lesions.