Five patients presenting with migraine attacks underwent Electroencephalography (EEC), Computed Tomography (CT) and Single Photon Emission Tomography (SPECT) with 99mTc-HM PAO. EEG and SPECT were subsequently repeated in the intercritical period. We observed that: two patients only showed non-specific abnormalities in EEG; scans were normal in all patients; all subjects exhibited diffuse cortical hypoperfusion. A strong correlation was always found between clinical presentation and hemispheric impairment. One patient exhibited asymmetrical perfusion between cerebellum hemispheres; intercritical SPECT showed homogeneous distribution of the radio-tracer in four patients. In the last one minimal residual hypoperfusion was observed, although less marked than in the acute phase. Therefore SPECT with 99mTc-HM PAO can be reasonably employed as the examination of choice when a migraine attack is clinically suspected, because of its reproducibility and reliability. It can be easily performed in every nuclear medical center supplied with modern tomographic gamma-cameras.