Abstract: This study was conducted to compare the effect of dexamethasone with dihydroergotamine on migraine attacks. A clinical study was carried out on 72 migraineurs, aged 15 to 55 years old. Patients who met the diagnostic criteria for migraine, as defined by the International Headache Society (HIS) were selected from the ones referred to emergency department. Patients received 1 mg dihydroergotamine (DHE) or 4 mg dexamethasone intravenously. Headache intensity was scored based on McGill method on a 1-15 point scale. Data were collected by questionnaires, which were filled on entry, 10 and 30 min after drug injections. The average frequency of migraine attacks was 2.2 per month and the duration of attacks was 12.2 h. The average score of headache intensity in start of study was 12.86. The intensity of headache 10 min after drug injection was less in both DHE and dexamethasone groups compared to the intensity of headache before drug injection (p<0.01). It was the same in both groups 30 min after injection of drugs compared to the intensity, 10 min after injection (p<0.01). There was no difference for intensity of headaches between two groups, 10 or 30 min after injection of DHE or dexamethasone. Twenty patients in DHE groups showed side effects, however, side effects was not seen in dexamethasone group. Therefore, dexamethasone seems to be a suitable alternative for ergot alkaloids in emergency migraine headaches.