195 patients with headache were examined by general practitioners and neurologists, and their diagnoses were compared. The general practitioners diagnosed migraine in 116 cases, the neurologists in 144 cases, and in 104 cases their diagnoses agreed. Thus, migraine can be difficult to diagnose, and this study indicates underdiagnosis of this common condition by general practitioners. This may result in overuse of analgesics and alternative therapies, and too little prescription of specific migraine medication. Greater familiarity with the diagnostic criteria of the International Headache Society should make it easier to arrive at a correct migraine diagnosis.