We compared computerized EEG spectral measures in patients with common migraine, tension headache, complicated migraine, and normal controls. One minute summaries of 4 sec EEG epochs were recorded fromOz-A1 + A2. Modal alpha frequency (MAF), the predominant frequency in the 8–13 Hz band, maximal alpha frequency (Mx AF), the fastest frequency in that band, and spectral edge frequency (SEF), the predominant frequency in the 13–30 Hz band, were calculated. EEG was also recorded from F3, F4, P3, P4, 01, and 02 with ear reference. Spectral mobility and first order complexity were compared in controls, migraineurs, and tension headache patients. Migraine and tension headache patients did not differ significantly, and were not different from control subjects in MAF and SEF. Complicated migraine patients had significantly lower MxAF than controls or common migraine patients (P<0.01). Patients with mixed element tension vascular headaches did not differ from controls in mobility or complexity at frontal, parietal or occipital sites. Mobility was significantly less at parietal and occipital sites in migraine patients (P<0.05). Complexity was less at both occipital electrodes(P<0.05) in the migraine group. Migraine patients had significantly lower occipital mobility and complexity scores than those with mixed element headaches (P<0.05).The findings suggest that computerized EEG analysis may help to categorize headache patients, and this may be therapeutically helpful. The time domain descriptors may be more sensitive to EEG differences than frequency or power measures. These observations suggest that migraine and mixed element headaches with amigrainous component may differ significantly in pathogenesis, and that central nervous system dysfunction may be involved in the pathogenesis of complicated migraine syndromes.