Purpose:Magnetic resonance defecography (MRD) has recently replaced conventional defecography (CD) which was, for decades, the mainstay exam for evaluation of obstructed defecation syndrome (ODS). Lack of widespread availability and high cost of MRD were major limitations that lead to intense need for other imaging alternatives. Echodefecography (EDF) is a recent imaging approach utilizing dynamic threedimensional ultrasound with good diagnostic capabilities. Methods: A prospective study was held on 15 patients with mean age of 41.4 years ± 16.8 years suffering from ODS. All included patients were subjected to detailed history taking and thorough physical examination followed by EDF and MRD. Certain measurements were acquired from images of both exams for comparison. Results: Rectocele was detected in 9 patients by EDF and 8 patients by MRD (fair statistical agreement was demonstrated between both modalities [ value 0.324]). 10 cases of anorectal descent were identified by EDF while MRD identified 14 cases (fair statistical agreement [ value 0.250]). EDF detected 6 cases of anismus, 10 cases of anorectal intussusception and 4 cases of enterocele whereas MRD did not identify any of these diagnoses (no statistics were computed because MRD is constant), however MRD detected 7 cases of cystocele and 5 cases of uterocele which cannot be visualized by EDF. Conclusion: EDF is of great capability of detecting different disorders of posterior pelvic compartment associated with ODS compared to MRD. Keywords: obstructed defecation, echodefecography, magnetic resonance defecography, rectocele, perineal descent.