Twenty-two patients whose electroclinical ictal characteristics suggested frontal lobe seizure foci were studied. Computed tomography (CT) scans showed abnormalities in only 32% of patients whereas magnetic resonance imaging was informative in 45%. 18FDG-Positron emission tomography (PET) scanning revealed decreased metabolism in 64% of the group. The areas of hypometabolism were focal, regional, or hemispheric. Focal frontal hypometabolism was significantly correlated with the electroclinical (semiologic) ictal localization. Therefore, FDG-PET scanning is a sensitive and specific technique for investigating patients with seizures of probable frontal lobe origins.