We describe seven patients who experienced a transient syndrome consisting of headache with neurologic deficits and CSF lymphocytic pleocytosis. Thirty-three similar patients have been reported previously. All had from one to more than 20 episodes of a severe migrainous headache accompanied by a temporary neurologic deficit and lymphocytes in the CSF. Some patients had a preceding viral syndrome, increased intracranial pressure, elevated CSF protein, or focal EEG abnormalities. All stopped having episodes within 3 months. We present diagnostic criteria for this benign syndrome. Its cause remains unknown.