BACKGROUND: There are a wide range of therapeutic options for migraine headaches that have different costs and benefits, and little is known about the cost-effectiveness of specific therapies. OBJECTIVE: Assess patients’ preferences for outcomes of treatment of migraine headache based on their marginal willingness to pay (WTP) for treatment attributes. METHODS: In an Internet-based study, we used computer software to measure importance ratings of attributes of pharmacological migraine therapies, then elicited their WTP for an ideal drug (one that was 100% effective, worked quickly, and had no adverse effects) and for "less than ideal" drugs with relatively poor performance in one specific attribute of performance. Patients: 429 self-identified migraineurs recruited via an Internet web site. RESULTS: A high proportion of patients in the study had symptoms consistent with migraine etiology of headache (91% in enrollees, 99% of patients providing WTP ratings). Expert review confirmed a large proportion of symptom profiles as being consistent with migraine (90% of the first 109 enrollees). Median WTP for an ideal migraine therapy was 4.1% of estimated monthly income or $130 (U.S.), and was associated with severity of pain, frequency of headaches, and the types of medications used in the past. WTP was reduced when pharmaceuticals offered less benefit (median reductions of a $75 per month for 50% chance of causing a rebound headache; $62 for rendering user unable to work, $50 for a two-hour delay in effect; and $15 for failure to relieve nausea). Reductions in WTP were largely consistent with importance ratings for attributes except for "speed of relief," which was more highly valued. CONCLUSIONS: Elicitation of patients’ WTP for specific attributes of a therapy appears to be a feasible method to quantify patients’ preferences for outcomes. Further work is needed to compare this approach to traditional methods for measurement of WTP.