Twenty-four patients with a clinical diagnosis of cerebrospinal fluid (CSF) fistulae who were assessed by MR are reported and the literature reviewed on the use of MR in the evaluation of CSF fistulae. Thirteen patients presented with rhinorrhoea, three had otorhinorrhoea and two had recurrent meningitis. Six patients had a combination of symptoms. Nine patients did not have active leakage of CSF at the time of MR scanning. The site of the CSF leak was identified in all 24 patients (100%) and was verified at operation in all patients. This study suggests that MR is a sensitive and accurate technique for detection of CSF leaks even in patients who are not actively leaking at the time of evaluation. MR imaging is a useful technique in the assessment of patients with CSF fistulae; it is non-invasive, offers excellent anatomical detail and has no radiation risk.