Background: Trigeminal neuralgia (TN) is still a serious neurologic condition that causes significant facial pain that is unilateral and is distributed across the trigeminal nerve. Magnetic resonance imaging (MRI) is an excellent imaging technique for determining the aetiology of TN, despite the fact that there are no particular clinical tests for its diagnosis. 3D FIESTA MRI helps to improve diagnostic precision and identify neurovascular compression when used in conjunction with conventional MRI. MRI is used to rule out alternative causes of TN, such as cerebellopontine angle lesions, demyelinating diseases, and inflammatory conditions, in addition to neurovascular compression. Aim of the Work: The objective of this study was to assess the utility of MRI in the diagnosis of TN and its various causes. Patients and Methods: In this prospective study, 30 patients (14 men and 16 women), with an average age of 49.6 years, were referred to Tanta University Hospital's Radiodiagnosis and Medical Imaging Department from outpatient neurosurgery and/or dental clinics. Results: The commonest affected side was the left side (46.7%) followed by the right one (40%), while bilateral affection was seen in (13.3%) of cases. According to aetiological factor, TN was secondary to underlying pathology in 24 cases (80%), while idiopathic TN with no underlying pathology was found in 6 cases (20%). Neurovascular compression and neoplastic lesions had the higher incidence. The most affected segment of the trigeminal nerve was the cisternal segment that was involved in 15 cases out of 24 cases with abnormal MRI findings. Conclusion: Many CPA lesions may cause TN such as schwannomas and meningiomas. Demyelinating disease as multiple sclerosis were reported in our study to cause also TN. MRI showed that it has significant diagnostic role denoting brain lesions in patients with TN as it has a diagnostic accuracy 62.5%, sensitivity 60% and specificity 100% (P < 0.001).