Background: MR spectroscopy is a non-invasive MR technique thatgives the relative concentrations of certain chemical metabolites of atissue. Changes in tissue metabolites may be useful for diagnosing andcharacterizing certain lesions.Objectives: To show the value of MR spectroscopy in detectingabnormal metabolite ratios concordant with the side of epileptic activity asdetected by the EEG.Patients & Methods: A total number of 50 patients withEEG lateralization of the epileptic activity scheduled for MRIand MR spectroscopy of the hippocampus and temporal cortexon both sides. Lateralization by MRS was compared to that bythe EEG study. Calculation of the metabolite ratios was doneto assess the extent of metabolite alteration outside thehippocampus of the same side, contralateral hippocampusand temporal cortex.Results: Our study revealed that MRS can accuratelylateralize the side of maximum affection of TLE in 86% ofcases.Conclusion: MR spectroscopy allows non-invasive correctlateralization of the epileptic focus concordant with the EEGlateralization, especially with the use of asymmetry index.MRS can also detect abnormal metabolite ratios in MRnegative patients with EEG lateralization.