This study examined the putative association of transient global amnesia (TGA) and migraine. 57 TGA patients were compared to a double-size control group of normal subjects. TGA patients who also had migraine were additionally compared to those without migraine and to a second control group of outpatients with migraine only. The prevalence of migraine, and also of episodic tension-type headache, was markedly increased among TGA patients. Precipitants and accompanying vegetative symptoms of TGA and migraine overlapped. However, there was no evidence of an interaction between TGA and migraine, in that the expression of key TGA features was not affected by comorbidity with migraine, and vice versa. The present findings argue against the hypothesis that TGA represents a type of migraine aura or migraine equivalent. They conform to the hypothesis that the two conditions are essentially independent and result from an inherited brain state that disposes to different types of paroxysmal dysregulation, presumably at the level of the brain stem.