PURPOSE: To determine the role of Tc-99m HMPAO SPECT imaging in children with intractable seizure by evaluating the interictal period. METHODS: We compared the EEG, CT and MRI medical records with those of Tc-99m HMPAO SPECT in 42 patients with intractable seizure referred to Kyunghee University Hospital, from April 1983 to September 1998, retrospectively. RESULTS: Mean age was 8.3 years and male to female ratio was 2.5 : 1. Multiple surface EEG recordings were performed in 42 patients and EEG findings of all patients showed an epileptogenic focus, with the most common area of abnormal findings being the Lt. sides. Brain CT was performed in 23 out of 42 patients(54.8%), and 15 out of the 23 patients(65.2%) showed abnormal findings and the most common area of abnormal findings were both sides. Brain MRI was performed in 21 out of 42 patients(50.0%), and 14 of the 21 patients(66.6%) showed abnormalities and the most common area of abnormal findings were both sides. In 32 out of the 42 patients (76.2%), SPECT images showed abnormal cerebral perfusion, most common area of hypoperfusion were Lt. sides. In 10 out of 14 cases, there were lateralizing abnormalities on the same side shown in SPECT and EEG, CT or MRI findings. CONCLUSION: We concluded that Tc-99m HMPAO SPECT seemed to be a useful tool in the evaluation of intractable seizure patients.