In addition to the wide expression in many tissues including vascular endothelial cells, production of angiotensin II and degradation of bradykinin may indicate that angiotensin-converting enzyme could be involved in vascular tension and blood pressure. It has been reported that the deletion allele of the angiotensin-converting enzyme gene is associated with increased serum angiotensin-converting enzyme levels and linked to cerebrovascular diseases. In this study, the possible association of migraine with aura with the angiotensin-converting enzyme deletion–deletion (DD) and the angiotensin–converting enzyme insertion–deletion (ID) genotype was investigated in Turkish patients. To investigate the role of the angiotensin-converting enzyme I/D polymorphism in Turkish patients with migraine with aura, we analyzed the I/D genotype of 53 patients with that disorder. Twenty-two control subjects, who are volunteer Turkish patients without migraine, were included in the study. The frequency of the angiotensin-converting enzyme D/D genotype was statistically significant more frequent in patients with migraine with aura (81.1%) than in controls (59.1%) (P < .05). No differences were found regarding the I/I genotype and the I/D genotype between the 2 groups (P > .05). The results of our study revealed that the angiotensin-converting enzyme D/D genotype was more frequent in patients with migraine with aura than in controls. This might suggest that the angiotensin-converting enzyme D/D genotype may be a genetic risk factor for migraine with aura in Turkish patients.