PURPOSE: To compare the reliability of lateralization between seizure semiology and ictal scalp EEG findings in mesial temporal lobe epilepsy (MTLE) patients, and to examine the advantage of the combined use of these two methods. METHODS: We independently reviewed the ictal scalp EEG recordings and clinical seizure semiology of 243 seizures recorded in 58 consecutive MTLE patients. All patients were seizure-free for at least 1 year postoperatively. Each seizure was lateralized on the basis of ictal semiology and ictal scalp EEG patterns according to strictly defined criteria, respectively. Individual patients were also lateralized based on these data. RESULTS: Seizure semiology analysis lateralized 64.6 % of seizures and 82.8 % of patients. Ictal scalp EEG analysis lateralized 74.5% of seizures and 74.1% of patients. Combination of the information from the two methods allowed for lateralization in a greater portion of both seizures (79.8%) and patients (89.7%). CONCLUSION: This study suggests that combination of ictal scalp EEG findings and seizure semiology improves the lateralization of individual seizures and patients. Therefore, it is worth lateralizing with standardized combined ictal EEG and semiology analysis for noninvasive presurgical evaluation in TLE patients.