Clinical observations show that migraine attacks have a seasonal, menstrual and circadian timing, suggesting a role of chronobiological mechanisms and their alterations in the disease, but little experimental data exists about this issue. The aim of this study was to estimate sleep quality chronotypes and the possible circadian timing of attacks in migraneurs. One hundred patients suffering from migraine without aura according to the IHS criteria (2004), and 30 controls were enrolled. Morning and evening type subjects were more represented in migraine patients than in controls and showed a tendency towards worse sleep quality and higher disability. Forty-two percent of migraineurs presented more than 75% of their attacks at night. Morning and evening types rather than intermediate and differences between real and preferred times may represent stressors that can worsen the disease. A preferential timing for occurrence of migraine attacks during the night and early morning hours was documented.