To evaluate availability of cerebral radionuclide imaging for diagnosis of brain death, we examined 25 patients with a suspected clinical diagnosis of brain death. 8 patients were studied by Tc-99m-DTPA and 15 patients were by Tc-99m-HMPAO (Hexamethyl propyleneamine oxime). Seven patients with Tc-99M-DTPA studies revealed absence of cerebral blood flow and sagittal sinus activity. All of 15 patients with Tc- 99m-HMPAO studies revealed complete absence of cerebral perfusion. The results of the cerebral radionuclide studies of brain death correlated with other clinical conditions, such as intracranial pressure(ICP), EEG, transcranial doppler sono- graphy(TCDS), and neurologic examination. The ICP of 8 patients, who are confirmed by brain death with Tc-99m-HMPAO study are elevated in all cases. In conclusion, cerebral radionuclide imaging for diagnosis of brain death is available. Tc-99m-HMPAO imaging is unequivocal, easily interpreted, well reflect the physiologic state of increased ICP, and provides adequate assessment of posterior fossa activity. In addition, the SPECT imaging with Tc-99m- HMPAO produces more accurate results due to it's superiority of image contrast and proper localization of radiopharmaceutical distribution than conventional planar imaging.