In a double-blind, cross-over study the effect and tolerance of the non-selective beta-blocker propranolol in a dosage of 80 mg twice daily was compared to that of the beta1 -selective beta-blocker metoprolol 200 mg once daily in Durules(r) (a controlled-release formulation). The attack frequency, migraine days, severity score, consumption of acute medication and subjective evaluation were the main parameters used for evaluation. Thirty-six patients with classical or common migraine were included. Thirty-three completed the investigation. It is concluded from the results that there are no differences in efficacy between metoprolol and propranolol regarding the studied parameters. Both drugs reduced the migraine symptoms compared to the run-in period and were generally well tolerated.