Traditionally the diagnosis of migraine has been made by clinical history, examination and investigation to exclude other ophthalmological and neurological diseases. To date there has been no simple objective test for the diagnosis of migraine on an individual basis. Patients were subjected to both flash and pattern light stimuli, and measurements were made from the resultant visual evoked potential (VEP) charted as a waveform. Calculations based on the parameters of the waveforms produced a Coefficient which correlated well with the medical diagnosis. This study demonstrates that electro-diagnostic methods can be utilised to provide a fast, reliable and accurate diagnosis for migraine on an individual basis, and which will also differentiate between the Common and Classical varieties.