A double-blind investigation with parallel groups was carried out in three Danish neurological clinics to evaluate the effect of metoprolol (Beloc, Betaloc, Seloken) versus placebo in migraine patients. 71 patients were included; 62 completed the study. The following parameters were used in the evaluation: frequency of headache attacks, days with migraine, severity score (days X intensity), and the consumption of pain-relieving tablets. The results of the study show that metoprolol 200 mg in Durules (a controlled release formulation) once daily is more effective regarding all evaluated parameters than placebo and that metoprolol is well tolerated.