Clinically the presence or absence of prodromes has always been regarded as the only distinctive feature differentiating classic migraine from common migraine. As a preliminary step for identifying any other distinctive clinical features peculiar to these two conditions, we thought it useful to review the clinical picture of classic migraine by investigating 164 patients (113 females and 51 males) aged 7-75 years. The prodromal phase consisted of scintillating scotomas (with hemianopic distribution in over half of the cases) in 79.3%, of paraesthesias mostly with cheiro-oral distribution in 29.9%, and of aphasic disturbances in 17.1%. When several neurological symptoms were present in the prodromal phase, their occurrence followed a regular sequence in time. The prodromes lasted less than 30 min in 75.6% of the cases. Only in about half the patients was pain contralateral to the peripheral location of the prodrome. The headache was generally not severe and short lived.