Background: Perianal fistula accounts for 0.01% of general population and is frequently managed inadequately resulting in a significant morbidity. Magnetic resonance imaging (MRI) plays an essential role in the preoperative assessment of the disease, therefore improving post-operative surgical outcome. Objective: To study the role of MRI in the evaluation of perianal fistula and to show the value of using contrast enhanced MR study in the determination of the precise tract pathway, extensions and other associated pathologies. Methods: A cross sectional analytic study was conducted on a total of 32 patients with perianal fistulas in the MRI Department of Al-Imamein Al-Kadhimein Medical City, Baghdad, Iraq during the period from November 2015 to December 2016. Patients underwent MRI examination using axial and coronal T2 weighted images with and without fat suppression and T1 fat suppressed sequences before and after contrast administration. The type of fistula, location of the internal opening, associated abscesses and/or sinus tracts and horseshoe extension were evaluated using different MR sequences. Results: The most common type of fistula encountered was the inter-sphincteric type, which was seen in 21 patients (66%), of those patients 16 fistulas (50%) were grade I and 5 fistulas (16%) were grade II. Trans-sphincteric fistulas were seen in 9 patients (28%), 2 of them (6%) were grade III and 7 fistulas (22%) were grade IV. Two patients (6%) had extra-sphincteric type. T2 weighted TSE, T2 TSE with fat suppression and T1 weighted fat suppressed post contrast sequences all show significant correlation with surgical results (with p-value less than 0.05) and the highest significance was obtained by the post contrast sequence (p-value of 0.00001). The highest accuracy in the diagnosis of fistula in ano was with the use of T1 enhanced fat suppressed sequence (98.8%) followed by 87% for the T2 fat suppression sequence and only 57% for the T2 weighted TSE sequence. Conclusion: MRI is an essential, noninvasive tool in the preoperative assessment of perianal fistulous tracks, with the axial and coronal post contrast fat suppression T1 providing the highest accuracy and clinical significance with surgical data and therefore giving a highly promising decrement in the incidence of post-operative complications. Keywords: MRI, perianal fistula Citation: Jawad AM, kadhim MA, Al-Jobouri ZK, Hussain MAA. The value of magnetic resonance imaging in the evaluation of peri-anal fistula. Iraqi JMS. 2018; 16(2): 166-176. doi: 10.22578/IJMS.16.2.8