In an attempt to categorize the diverse neurological manifestations of Behçet's syndrome, a group of 10 patients was prospectively studied; the diagnosis of Behçet's syndrome was not known in any of them prior to their neurological presentation. A reasonably clear distinction can be made to divide the manifestations into three general categories with some overlap. Category I includes patients with increased intracranial pressure with or without cerebral venous sinus thrombosis. Category II are those presenting with a stroke. Category III are those patients who present with spinal cord involvement and CSF pleocytosis. Brainstem involvement was noted independently of the group. In general, patients with Neuro-Behçet's syndrome showed little ocular involvement. The course of the illness both in morbidity and mortality tended to be better in category I, and mortality was only seen in category II patients. In populations susceptible to the disease, the clinical categorisation proposed may alert the clinician to the possibility of neuro-Behçet's syndrome whenever patients with pseudotumour cerebri, dural sinus thrombosis, stroke in the young, unexplained myelitis or possible multiple sclerosis are encountered.