Purpose: To reaffirm the role of MRI in the assessment of the M#159;llerian duct anomalies (MDAs)., Material and Methods: Between November 1997 and April 2001, 22 patients, age range 18-40 years (mean 29 years) were investigated with MRI and US. The MRI study was performed with a 0,5 Tesla imager (Vectra, GE Medical System) with body-coil; neither oral nor intravenous contrast was used. We obtained SE T1-weighted, fast STIR with fat suppression and FSE T2-weighted sequences. Sagittal, paracoronal and paraxial images were acquired. The paraxial images were obtained to produce true coronal images of the uterus. In evaluating MDAs, imaging the uterus in its true coronal plane is essential to assess the external fundal contour. US examination was performed with an HDI 3000, ATL, using the trans-vaginal approach. The MDAs were subdivided according to the Buttram and Gibbons classification., Results: There were 22 cases of laparoscopic and hysteroscopic proved anomalies; MRI allowed correct diagnosis of 21 uterine anomalies (accuracy, 95%) whereas U.S. was correct in 20 of 22 cases (accuracy, 92%). The MRI was excellent in depicting the uterine morphology in one case of unicornuate uterus with rudimentary horn non-comunicating with the main cavity and distended by hematometra and associated hematosalpinx. Further-more evaluating composition, thickness and extension of the uterine septum and aspect of the fundal contour, MRI allowed to differentiate definitively between bicornuate uterus and septate uterus. This is a very important distinction to do because it significantly affects patient treatment: a septate uterus requires hysteroscopic septectomy, while a bicornuate uterus does not requires surgical treatment., Conclusions: Given its characteristics, MRI is a very accurate imaging modality in uterine evaluation and contributes significantly to treatment planning. Although ultrasonography remains the modality of choice for the initial study of patients who are suspected of having a MDAs, we propose, in accordance with many authors in the literature, to reserve MRI imaging for patients with a technically inadequate or indeterminate ultrasound examination.