We examined the distribution of HLA-DRB1 alleles in a cohort 255 Italian migraine patients and in a control group of 325 healthy subjects. 214 patients fulfilled the ICHD-II criteria for migraine without aura and 41 patients the criteria for migraine with aura. The frequency of DRB1*16 allele was found to be significantly increased in migraine without aura patients (p=0.02; OR 1.97, 95% CI: 1.10-3.54) than in healthy controls. The frequencies of HLA-DRB1 alleles were not significantly different between migraine with aura patients and controls. We did not detect any effect of DRB1 alleles on age at onset, duration of the disease, frequency and duration of migraine attacks. Our data suggest the presence of a genetic susceptibility factor for migraine without aura within the HLA region.