Migraine is frequently undertreated, perhaps because impaired communication between patients and physicians underestimate the disability associated with migraine attacks. The purpose of this study was to evaluate the benefits of a structured migraine diary used during a prospective open-label study of triptan-naive patients in Spain for recording information on response to therapy for a pre-study migraine attack and three consecutive migraine attacks, the first and third treated with rizatriptan 10-mg wafer and the second with usual non-triptan therapy. Of 97 patients (83% women; mean age, 39 years) who completed the study, all reported moderate to severe pain, and two-thirds reported severe to total impairment during migraine attacks. At study end, 72% of patients reported that the migraine diary helped communication with their doctor about migraine, and 70% were more or much more satisfied than before the study with level of overall medical care provided by their doctor. Patients who reported the diary to be useful also reported higher overall satisfaction with medical care (p < 0.001). Most of the 22 physicians (91%) reported that the diary enabled them to better communicate with their patients about migraine, and all reported that it enabled them to assess differences in pain intensity and disability across patients. We conclude that a structured migraine diary can be a valuable aid for improving communication between physicians and patients regarding migraine disability and treatment outcomes.