OBJECTIVE: To provide physicians and allied health care professionals with guidelines for the diagnosis and management of migraine in clinical practice. OPTIONS: The full range and quality of diagnostic and therapeutic methods available for the management of migraine. OUTCOMES: Improvement in the diagnosis and treatment of migraine, which will lead to a reduction in suffering, increased productivity and decreased economic burden. EVIDENCE AND VALUES: The creation of the guidelines followed a needs assessment by members of the Canadian Headache Society and included a statement of objectives; development of guidelines by multidisciplinary working groups using information from literature reviews and other resources; comparison of alternative clinical pathways and description of how published data were analysed; definition of the level of evidence for data in each case; evaluation and revision of the guidelines at a consensus conference held in Ottawa on Oct. 27-29, 1995; redrafting and insertion of tables showing key variables and data from various studies and tables of data with recommendations; and reassessment by all conference participants. BENEFITS, HARMS AND COSTS: Accuracy in diagnosis is a major factor in improving therapeutic effectiveness. Improvement in the precise diagnosis of migraine, coupled with a rational plan for the treatment of acute attacks and for prophylactic therapy, is likely to lead to substantial benefits in both human and economic terms. RECOMMENDATIONS: The diagnosis of migraine can be improved by using modified criteria of the International Headache Society as well as a semistructured patient interview technique. Appropriate treatment of symptoms should take into account the severity of the migraine attack, since most patients will have attacks of differing severity and can learn to use medication appropriate for each attack. When headaches are frequent or particularly severe, prophylactic therapy should be considered. Both the avoidance of migraine trigger factors and the application of nonpharmacological therapies play important roles in overall migraine management and will be addressed at a later date. VALIDATION: The guidelines are based on consensus of Canadian experts in neurology, emergency medicine, psychiatry, psychology, family medicine and pharmacology, and consumers. Previous guidelines did not exist. Field testing of the guidelines is in progress.