Several studies have shown that migraine is associated with an abnormal platelet activation state, characterized by increased plasma levels of platelet BTG and PF4 proteins. Adenine nucleotides are contained in platelets as a part of the dense granules released during platelet activation. In the present study we evaluated the plasma levels of the adenine nucleotides AMP, ADP and ATP during asymptomatic and painful episodes in a group of 50 patients with migraine (common and classical) and a control group. During the painful phases we found a significant reduction in AMP plasma levels, and we did not find significant differences between the control group and the migraine patients in ADP and ATP levels, nor between asymptomatic and painful phases. Our results support the hypothesis that in migraine a hyposecretion of platelet dense granules is present.