We evaluated 58 pediatric patients (39 females) suffering from various kinds of migraine in order to assess the prevalence of mitral valve prolapse, using echocardiography, and platelet function, using standard platelet aggregation tests. The patients were grouped as follows: 14 subjects with muscle contraction headache, 9 subjects with common migraine, 13 subjects with classic migraine, 22 subjects with complicated migraine. We examined as a control group 30 normal subjects matched for age and sex with the patients. Prevalence of MVP in subjects with complicated migraine (59%) was significantly higher as compared to the other groups of patients ( r <0.005) and to the control group ( r <0.0005). The prevalence of MVP in subjects with classic and common migraine (13.6%) was slightly, but not significantly higher than in the control group (6.7%). No significant differences in platelet aggregation tests were observed either between groups of migraine sufferers and controls, or between subjects with and without MVP. We suggest that the association between MVP and complicated migraine is not coincidence, and that follow-up studies are needed to assess its clinical significance.