The authors report the first invasive electroencephalography (EEG) monitoring in Thailand in a patient who had intractable left temporal lobe epilepsy. The seizure origin and functioning cortices were identified The corresponding epileptogenic zone was resected without functional deficit. The patient has become seizure free 1 year since surgery. Subdural EEG monitoring with cortical stimulation have been developed at this tertiary epilepsy center The technique provides essential evidence for the surgical decision so that the best post operative outcome can be achieved.