The effect of migraine on the prognosis of epilepsy has not been reported. Th e aim of this prospective 5- 10- year follow- up study was to examine some ou tcome measures and the cumulative probability of being seizure- free in epileps y patients with migraine, and to compare their results with those of epilepsy pa tients without migraine. Fifty- nine patients (40 women; mean age 25 years) wer e diagnosed with both epilepsy and migraine (EM group). The control group consis ted of 56 patients with epilepsy but without migraine (E group). Both groups were recruited and followed up over similar periods. W e compared the outcome variables in the EM group with those in the E group. Kapl an- Meier methods were used to assess the seizurefree curves. The EM group had a significantly lower cumulative probability of being seizure- free over 10 yea rs compared with the E group. The other epilepsy outcome measures at follow- up differed significantly between the groups, with the EM group having a longer du ration of epilepsy, a lower early treatment response, and a higher incidence of intractable epilepsy and achieving remission with polytherapy, and more seizure control and medication problems for at least the last 2 years of followup. Comor bid migraine had a negative effect on the prognosis of epilepsy. The effect of migraine on the prognosis of epilepsy has not been reported. Th e aim of this prospective 5- 10-year follow-up study was to examine some ou tcome measures and the cumulative probability of being seizure-free in epileps y patients with migraine, and to compare their results with those of epilepsy pa tients without migraine. Fifty-nine patients (40 women; mean age 25 years) wer e diagnosed with both epilepsy and migraine (EM group). The control group consisted of 56 patients with epilepsy but without migraine (E group). Both groups were recruited and followed up over similar periods. W e compared the outcome variables in the EM group with those in the E group. Kapl an- Meier methods were used to assess the seizure free curves The EM group had a significantly lower cumulative probability of being seizure- free over 10 yea rs compared with the E group. The other epilepsy outcome measures at follow- up differed significantly between the groups, with the EM group having a longer du ration of epilepsy, a lower early treatment response, and a higher incidence of intractable epilepsy and achieving remission with polytherapy, and more seizure control and medication problems for at least the last 2 years of followup. Comor bid migraine had a negative effect on the prognosis of epilepsy.